migration-tcp: call migrate_fd_error() instead of close() and free().

This patch fixes the following error report.  When changing
migration-tcp.c to call migrate_fd_error() instead of close() and
free() by itself, monitor is resumed, and returns allocated mig_state
is set to current_migration in migration.c allows us to print "info
migrate".
Reported-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NYoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

migration-tcp.c

@@ -128,9 +128,7 @@ MigrationState *tcp_start_outgoing_migration(Monitor *mon,
 
     if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
         DPRINTF("connect failed\n");
-        close(s->fd);
-        qemu_free(s);
-        return NULL;
+        migrate_fd_error(s);
     } else if (ret >= 0)
         migrate_fd_connect(s);