glocalfileoutputstream: Fix an FD leak in an error path
glocalfileoutputstream: Fix an FD leak in an error path

If a backup file is created, opened successfully, then fstat() on it
fails (perhaps due to another process deleting it in the mean time?),
the FD will be leaked.

Coverity issue: #1159485

https://bugzilla.gnome.org/show_bug.cgi?id=730187

endlessm/glib,endlessm/glib,endlessm/glib,johne53/MB3Glib,johne53/MB3Glib,endlessm/glib,johne53/MB3Glib,johne53/MB3Glib,johne53/MB3Glib,endlessm/glib,johne53/MB3Glib