rpcbind: avoid entering failed status after stopping daemon

Exiting with '2' is actually expected with rpcbind, because it catches
SIGTERM and exits with '2' explicitly.

The related code is as follows.

(void) signal(SIGTERM, terminate);

/*
 * Catch the signal and die
 */
static void
terminate(int dummy /*__unused*/)
{
        close(rpcbindlockfd);
        unlink(_PATH_RPCBINDSOCK);
        unlink(RPCBINDDLOCK);
        syslog(LOG_ERR,
                "rpcbind terminating on signal. Restart with \"rpcbind -w\"");
        write_warmstart(); /* Dump yourself */
        exit(2);
}

(From OE-Core rev: 1bfc6a45e7ba81d3537ea3ae8b176f5a9c206eaa)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/rpcbind/rpcbind/rpcbind.service

@@ -9,6 +9,7 @@ Type=forking
 EnvironmentFile=-@SYSCONFDIR@/rpcbind.conf
 ExecStart=@SBINDIR@/rpcbind -w $RPCBIND_OPTS
 Restart=always
+SuccessExitStatus=2
 
 [Install]
 WantedBy=multi-user.target