Restrict "node_name" to maximum 63 characters

In "recovery.conf", the configuration parameter "node_name" is used
as the "application_name" value, which will be truncated by PostgreSQL
to 63 characters (NAMEDATALEN - 1).

repmgr sometimes needs to be able to extract the application name from
pg_stat_replication to determine if a node is connected (e.g. when
executing "repmgr standby register"), so the comparison will fail
if "node_name" exceeds 63 characters.

configfile.h

@@ -76,7 +76,7 @@ typedef struct
 {
 	/* node information */
 	int			node_id;
-	char		node_name[MAXLEN];
+	char		node_name[NAMEDATALEN];
 	char		conninfo[MAXLEN];
 	char		replication_user[NAMEDATALEN];
 	char		data_directory[MAXPGPATH];