Add "--checksum" in rsync when using "--force"

If the user don't put that option in rsync_options using of "--force"
could be unsafe.
While the probability of failures because of this are low they aren't
zero.

repmgr.c

@@ -28,6 +28,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
 
@@ -125,7 +126,7 @@ main(int argc, char **argv)
 	}
 
 
-	while ((c = getopt_long(argc, argv, "d:h:p:U:D:f:R:w:k:F:I:v", long_options,
+	while ((c = getopt_long(argc, argv, "d:h:p:U:D:f:R:w:k:FIv", long_options,
 	                        &optindex)) != -1)
 	{
 		switch (c)
@@ -255,7 +256,7 @@ main(int argc, char **argv)
 		break;
 	default:
 		log_err(_("%s: too many command-line arguments (first extra is \"%s\")\n"),
-		        progname, argv[optind + 1]);
+		        progname, argv[optind]);
 		usage();
 		exit(ERR_BAD_CONFIG);
 	}
@@ -1603,11 +1604,18 @@ test_ssh_connection(char *host, char *remote_user)
 	char script[MAXLEN];
 	int	 r;
 
+	/* On some OS, true is located in a different place than in Linux */
+#ifdef __FreeBSD__
+#define TRUEBIN_PATH "/usr/bin/true"
+#else
+#define TRUEBIN_PATH "/bin/true"
+#endif
+
 	/* Check if we have ssh connectivity to host before trying to rsync */
 	if (!remote_user[0])
-		maxlen_snprintf(script, "ssh -o Batchmode=yes %s /bin/true", host);
+		maxlen_snprintf(script, "ssh -o Batchmode=yes %s %s", host, TRUEBIN_PATH);
 	else
-		maxlen_snprintf(script, "ssh -o Batchmode=yes %s -l %s /bin/true", host, remote_user);
+		maxlen_snprintf(script, "ssh -o Batchmode=yes %s -l %s %s", host, remote_user, TRUEBIN_PATH);
 
 	log_debug(_("command is: %s"), script);
 	r = system(script);
@@ -1633,7 +1641,7 @@ copy_remote_files(char *host, char *remote_user, char *remote_path,
 		maxlen_snprintf(rsync_flags, "%s", options.rsync_options);
 
 	if (runtime_options.force)
-		strcat(rsync_flags, " --delete");
+		strcat(rsync_flags, " --delete --checksum");
 
 	if (!remote_user[0])
 	{
@@ -1832,20 +1840,24 @@ write_primary_conninfo(char* line)
 
 	/* Environment variable for password (UGLY, please use .pgpass!) */
 	const char *password = getenv("PGPASSWORD");
-    if (password != NULL) {
+	if (password != NULL)
+	{
 		maxlen_snprintf(password_buf, " password=%s", password);
 	}
-    else if (require_password) {
+	else if (require_password)
+	{
 		log_err(_("%s: PGPASSWORD not set, but having one is required\n"),
 		        progname);
 		exit(ERR_BAD_PASSWORD);
 	}
 
-    if (runtime_options.host[0]) {
+	if (runtime_options.host[0])
+	{
 		maxlen_snprintf(host_buf, " host=%s", runtime_options.host);
 	}
 
-    if (runtime_options.username[0]) {
+	if (runtime_options.username[0])
+	{
 		maxlen_snprintf(user_buf, " user=%s", runtime_options.username);
 	}