Failed to resolve path '/var/opt/gitlab/git-data-alt/repositories/s2gluser/gitlab-ee.git': No such file or directory

@eReGeBe @yorickpeterse this error was found by @connorshea while he was visiting https://staging.gitlab.com/gitlab-org/gitlab-ce/merge_requests, I think @yorickpeterse was trying to move some repositories.

Here is the Sentry issue: https://sentry.gitlap.com/gitlab/staginggitlabcom/issues/10348/

Here is a part of the backtrace:

Rugged::OSError: Failed to resolve path '/var/opt/gitlab/git-data-alt/repositories/s2gluser/gitlab-ee.git': No such file or directory
  from lib/gitlab/metrics/instrumentation.rb:155:in `new'
  from lib/gitlab/metrics/instrumentation.rb:155:in `block in new'
  from lib/gitlab/metrics/method_call.rb:23:in `measure'
  from lib/gitlab/metrics/instrumentation.rb:155:in `new'
  from gitlab_git/repository.rb:50:in `rugged'
  from lib/gitlab/metrics/instrumentation.rb:155:in `block in rugged'
  from lib/gitlab/metrics/method_call.rb:23:in `measure'
  from lib/gitlab/metrics/instrumentation.rb:155:in `rugged'
  from gitlab_git/repository.rb:73:in `local_branches'
  from lib/gitlab/metrics/instrumentation.rb:155:in `block in local_branches'
  from lib/gitlab/metrics/method_call.rb:23:in `measure'
  from lib/gitlab/metrics/instrumentation.rb:155:in `local_branches'
  from app/models/repository.rb:784:in `local_branches'
  from lib/gitlab/metrics/instrumentation.rb:155:in `block in branches'
  from lib/gitlab/metrics/method_call.rb:23:in `measure'
  from lib/gitlab/metrics/instrumentation.rb:155:in `branches'
  from app/models/repository.rb:259:in `block in branch_names'
  from active_support/cache.rb:299:in `block in fetch'
  from active_support/cache.rb:585:in `block in save_block_result_to_cache'
  from active_support/cache.rb:547:in `block in instrument'
  from active_support/notifications.rb:164:in `block in instrument'
  from active_support/notifications/instrumenter.rb:20:in `instrument'
  from active_support/notifications.rb:164:in `instrument'
  from active_support/cache.rb:547:in `instrument'
  from active_support/cache.rb:584:in `save_block_result_to_cache'
  from active_support/cache.rb:299:in `fetch'
  from lib/repository_cache.rb:20:in `fetch'
  from app/models/repository.rb:259:in `branch_names'
  from lib/gitlab/metrics/instrumentation.rb:155:in `block in branch_names'
  from lib/gitlab/metrics/method_call.rb:23:in `measure'
  from lib/gitlab/metrics/instrumentation.rb:155:in `branch_names'
  from app/models/merge_request.rb:516:in `source_branch_exists?'
  from lib/gitlab/metrics/instrumentation.rb:155:in `block in source_branch_exists?'
  from lib/gitlab/metrics/method_call.rb:23:in `measure'
  from lib/gitlab/metrics/instrumentation.rb:155:in `source_branch_exists?'
  from app/models/merge_request.rb:682:in `branch_missing?'
  from lib/gitlab/metrics/instrumentation.rb:155:in `block in branch_missing?'
  from lib/gitlab/metrics/method_call.rb:23:in `measure'
  from lib/gitlab/metrics/instrumentation.rb:155:in `branch_missing?'
  from app/models/merge_request.rb:686:in `broken?'