qemu-ga: Plug fd leak on ga_channel_listen_accept() error path

Spotted by Coverity.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

qga/channel-posix.c

diff --git a/qga/channel-posix.c b/qga/channel-posix.c
index ca9e4aa..9a5c05d 100644
--- a/qga/channel-posix.c
+++ b/qga/channel-posix.c
@@ -46,6 +46,7 @@
     ret = ga_channel_client_add(c, client_fd);
     if (ret) {
         g_warning("error setting up connection");
+        close(client_fd);
         goto out;
     }
     accepted = true;