pg_upgrade: quote directory names in delete_old_cluster script

This allows the delete script to properly function when special
characters appear in directory paths, e.g. spaces.

Backpatch through 9.0

contrib/pg_upgrade/check.c

@@ -483,7 +483,7 @@ create_script_for_old_cluster_deletion(
 #endif
 
 	/* delete old cluster's default tablespace */
-	fprintf(script, RMDIR_CMD " %s\n", fix_path_separator(old_cluster.pgdata));
+	fprintf(script, RMDIR_CMD " \"%s\"\n", fix_path_separator(old_cluster.pgdata));
 
 	/* delete old cluster's alternate tablespaces */
 	for (tblnum = 0; tblnum < os_info.num_tablespaces; tblnum++)
@@ -507,7 +507,7 @@ create_script_for_old_cluster_deletion(
 
 			for (dbnum = 0; dbnum < new_cluster.dbarr.ndbs; dbnum++)
 			{
-				fprintf(script, RMDIR_CMD " %s%s%c%d\n",
+				fprintf(script, RMDIR_CMD " \"%s%s%c%d\"\n",
 						fix_path_separator(os_info.tablespaces[tblnum]),
 						fix_path_separator(old_cluster.tablespace_suffix),
 						PATH_SEPARATOR, old_cluster.dbarr.dbs[dbnum].db_oid);
@@ -519,7 +519,7 @@ create_script_for_old_cluster_deletion(
 			 * Simply delete the tablespace directory, which might be ".old"
 			 * or a version-specific subdirectory.
 			 */
-			fprintf(script, RMDIR_CMD " %s%s\n",
+			fprintf(script, RMDIR_CMD " \"%s%s\"\n",
 					fix_path_separator(os_info.tablespaces[tblnum]), 
 					fix_path_separator(old_cluster.tablespace_suffix));
 	}