Fixed failing functional tests in groups_controller_test.rb

This fixes the following two failing functional tests:

```
  1) Failure:
test: An authenticated and authorized admin doing a POST on :add_group should be able to add group without groupname. (GroupsControllerTest) [test/functional/groups_controller_test.rb:114]:
<nil> expected to not be nil.

  2) Failure:
test: An authenticated and authorized admin doing a POST on :add_group should be able to create with groupname. (GroupsControllerTest) [test/functional/groups_controller_test.rb:124]:
<nil> expected to not be nil.
```