As of 3.19.0 glade supports Python3 [0] also the Pyhon3 as default change was accepted (under different name) which implies that all packages shipped on LiveCD must run on Python3. Please switch your package to use python3. [0] http://lists.ximian.com/pipermail/glade-devel/2015-June/002090.html
Thanks, fixed in http://pkgs.fedoraproject.org/cgit/glade.git/commit/?id=14ea8aaca3bbb720a98125483d7633fba44b396f