Add GitError

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Use GitError instead of RuntimeError

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Add retries to fetch_qa_suite()

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>