Remove hooks directory creation from `repo` helper

This helper previously created a `.git/hooks` directory for every
repository. This wasn't necessary since we only needed this for a few
tests. Fix those tests to create the hooks directory instead.

Change-Id: I8ef18d6136c02c4306bb8d5453937f8030e95d63
Reviewed-on: http://gerrit.causes.com/45272
Tested-by: jenkins <jenkins@brigade.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>