PyGProps_getattro(): Fix GObjectClass leak
PyGProps_getattro(): Fix GObjectClass leak

https://bugzilla.gnome.org/show_bug.cgi?id=685218

sfeltman/pygobject,sfeltman/pygobject,GNOME/pygobject,davibe/pygobject,davibe/pygobject,davibe/pygobject,pexip/pygobject,GNOME/pygobject,sfeltman/pygobject,GNOME/pygobject,davibe/pygobject,pexip/pygobject,pexip/pygobject