xwayland: don't close() fds we don't own

The glamor_pixmap_from_fds error path erroneously closes the fds.
We don't own them, plus the caller closes them after the function in
called.

Fixes: cef12efc15 ("glamor: Implement GetSupportedModifiers")
Cc: Louis-Francis Ratté-Boulianne <lfrb@collabora.com>
Cc: Daniel Stone <daniels@collabora.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>

hw/xwayland/xwayland-glamor.c

@@ -704,8 +704,6 @@ glamor_pixmap_from_fds(ScreenPtr screen,
     return pixmap;
 
 error:
-    for (i = 0; i < num_fds; i++)
-       close(fds[i]);
     return NULL;
 }