"node rejoin": actively check for node to rejoin cluster

Previously repmgr was relying on whatever command was configured to
start PostgreSQL to determine whether the node being rejoined had
started correctly. However it's preferable to actively poll the upstream
to confirm it has restarted and actually attached as a standby before
confirming success of the "node rejoin" action.

This can be overridden with the -W/--no-wait option.

(Note that for consistency with other PostgreSQL utilities, the
short form of the --wait option is now "-w"; this is currently
only used in "repmgr standby follow".)

Also update "repmgr node rejoin" documentation with a list of supported
options, and add some useful index entries for "pg_rewind".

Implements GitHub #415.

doc/repmgr-node-rejoin.sgml

@@ -45,6 +45,77 @@
     </para>
   </refsect1>
 
+  <refsect1>
+
+    <title>Options</title>
+    <variablelist>
+
+      <varlistentry>
+        <term><option>--dry-run</option></term>
+        <listitem>
+          <para>
+            Check prerequisites but don't actually execute the rejoin.
+          </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>--force-rewind[=/path/to/pg_rewind]</option></term>
+        <listitem>
+          <para>
+            Execute <application>pg_rewind</application> if necessary.
+          </para>
+          <para>
+            It is only necessary to provide the <application>pg_rewind</application>
+            if using PostgreSQL 9.3 or 9.4, and <application>pg_rewind</application>
+            is not installed in the PostgreSQL <filename>bin</filename> directory.
+          </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>--config-files</option></term>
+        <listitem>
+          <para>
+            comma-separated list of configuration files to retain after
+            executing <application>pg_rewind</application>.
+          </para>
+          <para>
+            Currently <application>pg_rewind</application> will overwrite
+            the local node's configuration files with the files from the source node,
+            so it's advisable to use this option to ensure they are kept.
+          </para>
+        </listitem>
+      </varlistentry>
+
+
+      <varlistentry>
+        <term><option>--config-archive-dir</option></term>
+        <listitem>
+          <para>
+            Directory to temporarily store configuration files specified with
+            <option>--config-files</option>; default: <filename>/tmp</filename>.
+          </para>
+        </listitem>
+      </varlistentry>
+
+
+      <varlistentry>
+        <term><option>-W/--no-wait</option></term>
+        <listitem>
+          <para>
+            Don't wait for the node to rejoin cluster.
+          </para>
+          <para>
+            If this option is supplied, &repmgr; will restart the node but
+            not wait for it to connect to the primary.
+          </para>
+        </listitem>
+      </varlistentry>
+
+    </variablelist>
+  </refsect1>
+
   <refsect1>
     <title>Event notifications</title>
     <para>
@@ -77,11 +148,18 @@
   </refsect1>
 
   <refsect1 id="repmgr-node-rejoin-pg-rewind" xreflabel="Using pg_rewind">
+
+   <indexterm>
+      <primary>pg_rewind</primary>
+      <secondary>using with "repmgr node rejoin"</secondary>
+    </indexterm>
+
     <title>Using <command>pg_rewind</command></title>
     <para>
       <command>repmgr node rejoin</command> can optionally use <command>pg_rewind</command> to re-integrate a
       node which has diverged from the rest of the cluster, typically a failed primary.
-      <command>pg_rewind</command> is available in PostgreSQL 9.5 and later.
+      <command>pg_rewind</command> is available in PostgreSQL 9.5 and later as part of the core distribution,
+      and can be installed from external sources for PostgreSQL 9.3 and 9.4.
     </para>
     <note>
       <para>

doc/repmgr-standby-follow.sgml

@@ -71,7 +71,7 @@
       </varlistentry>
 
       <varlistentry>
-        <term><option>-W</option></term>
+        <term><option>-w</option></term>
         <term><option>--wait</option></term>
         <listitem>
           <para>

doc/switchover.sgml

@@ -180,6 +180,10 @@
    </note>
 
   <sect2 id="switchover-pg-rewind" xreflabel="Switchover and pg_rewind">
+    <indexterm>
+      <primary>pg_rewind</primary>
+      <secondary>using with "repmgr standby switchover"</secondary>
+    </indexterm>
     <title>Switchover and pg_rewind</title>
     <para>
       If the demotion candidate does not shut down smoothly or cleanly, there's a risk it
@@ -206,7 +210,7 @@
     </para>
     <para>
       <application>pg_rewind</application> has been part of the core PostgreSQL distribution since
-      version 9.5. Users of versions 9.3 and 9.4 will need to manually install; source code available here:
+      version 9.5. Users of versions 9.3 and 9.4 will need to manually install it; the source code is available here:
       <ulink url="https://github.com/vmware/pg_rewind">https://github.com/vmware/pg_rewind</ulink>.
       If the <application>pg_rewind</application>
       binary is not installed in the PostgreSQL <filename>bin</filename> directory, provide