Move repo checkout code to new module repo_utils

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

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

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Handle ceph-qa-suite checkouts

Previously we had an internally-maintained shell script that did this.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Also handle teuthology repo checkouts

Our shell script did this also.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Use 'ceph-qa-suite.git' for the repo name

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