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>
 
@@ -117,7 +118,7 @@ main(int argc, char **argv)
 	}
 
 
-	while ((c = getopt_long(argc, argv, "d:h:p:U:D:f:R:w:F:I:v", long_options,
+	while ((c = getopt_long(argc, argv, "d:h:p:U:D:f:R:w:FIv", long_options,
 	                        &optindex)) != -1)
 	{
 		switch (c)
@@ -232,7 +233,7 @@ 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);
 	}
@@ -861,6 +862,7 @@ do_standby_clone(void)
 				PQfinish(conn);
 				exit(ERR_BAD_CONFIG);
 			}
+			break;
 		default:
 			/* Trouble accessing directory */
 			log_err(_("%s: could not access directory \"%s\": %s\n"),
@@ -887,6 +889,16 @@ do_standby_clone(void)
 		PQfinish(conn);
 		exit(ERR_BAD_CONFIG);
 	}
+	
+	/* We need all 4 parameters, and they can be retrieved only by superusers */
+	if (PQntuples(res) != 4)
+	{
+		log_err("%s: STANDBY CLONE should be run by a SUPERUSER\n", progname);
+		PQclear(res);
+		PQfinish(conn);
+		exit(ERR_BAD_CONFIG);
+	}
+
 	for (i = 0; i < PQntuples(res); i++)
 	{
 		if (strcmp(PQgetvalue(res, i, 0), "data_directory") == 0)
@@ -1476,7 +1488,7 @@ 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])
 	{