qemu-ga: ask and print error information from qemu-sockets

Reviewed-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

qga/channel-posix.c

@@ -181,9 +181,11 @@ static gboolean ga_channel_open(GAChannel *c, const gchar *path, GAChannelMethod
         break;
     }
     case GA_CHANNEL_UNIX_LISTEN: {
-        int fd = unix_listen(path, NULL, strlen(path), NULL);
-        if (fd == -1) {
-            g_critical("error opening path: %s", strerror(errno));
+        Error *local_err = NULL;
+        int fd = unix_listen(path, NULL, strlen(path), &local_err);
+        if (local_err != NULL) {
+            g_critical("%s", error_get_pretty(local_err));
+            error_free(local_err);
             return false;
         }
         ga_channel_listen_add(c, fd, true);