Handle AlreadyExists errors in CreateRepository
In order to be able to use proper transactional locking semantics in Gitaly, we need to convert CreateRepository and related RPCs to not touch existing repositories. We'll thus changes those RPCs to create AlreadyExists
errors in case the target repository already exists. This is a breaking change at least for CreateRepository, which previously was idempotent and thus just called git-init(1) on preexisting repositories.
Edited by Patrick Steinhardt