[toolforge-deploy] fix bug in setup_toolforge_deploy
- default to main if branch not in repo. this fixes tests for packages too
-
git reset --hard origin/branchinstead ofFETCH_HEAD.
This is becausegit fetch --alldoes not updateFETCH_HEAD
Bug: T358225
Signed-off-by: raymond-ndibe rndibe@wikimedia.org