Fix Coverity CID 978183 Resource leak in rexec().

Close the socket if connect() fails to avoid leaking it.

Reported by:	Coverity
CID:		978183
MFC after:	1 week

lib/libcompat/4.3/rexec.c

@@ -330,6 +330,7 @@ rexec(ahost, rport, name, pass, cmd, fd2p)
 			goto retry;
 		}
 		perror(hp->h_name);
+		(void) close(s);
 		return (-1);
 	}
 	port = 0;