Added 'group_update' missing route to catalog explorer.

DRYed up spec test.

https://bugzilla.redhat.com/show_bug.cgi?id=1159353
https://bugzilla.redhat.com/show_bug.cgi?id=1159354
Merge pull request #960 from h-kataria/added_missing_route_for_group_update

Added 'group_update' missing route to catalog explorer.