Ensure no old gems are left behind between test runs.
Run bundle clean after bundle install

Running it beforehand was resulting in a corrupted state
if it was the first time bundle install was run.
removes qualaroo from studio (STUD-1684)
Delete orphans was trying to get non-existent 'draft' modulestore
Merge pull request #3932 from edx/dhm/bug_orphans

Delete orphans was trying to get non-existent 'draft' modulestore
Merge pull request #3937 from edx/adam/remove-qualaroo-studio

removes qualaroo from studio (STUD-1684)
Merge pull request #3919 from edx/benpatterson/clean-up-rbenv

Ensure no old gems are left behind between test runs.
Reuse course creator user in bok-choy tests and have them not be global staff
Move user to course fixture