Bamboo shouldn't attempt to run branch detection or branch expiry when default repository is changed to one that doesn't support it

Issue Summary

Bamboo shouldn't continue to run branch detection or branch expiry when default repository is changed to one that doesn't support it. E.g. CVS or Perforce. This creates unnecessary errors logged against the plan in the UI and warnings in the logs stating:

Can't detect branches for plan PROJ-PLAN - its default repository does not support automatic branch detection

Steps to Reproduce

1. Add a plan with Bitbucket Server repository
2. Enable branch detection and expiry at Plan Configuration >> Branches
3. Remove the repository and add a CVS repository

Expected Results

Branch detection and expiry is not executed for this plan since it's not supported for the repository and no warnings are displayed or logged.

Actual Results

Branch detection and expiry continues to run for the plan.

The below warning is shown in the atlassian-bamboo.log file and in the UI when viewing the plan:

2019-01-30 16:11:35,776 WARN [11-BranchDetectionBackgroundThread:pool-18-thread-2] [BranchDetectionServiceImpl] Can't detect branches for plan NEW2-MER - its default repository does not support automatic branch detection

Workaround

1. Add a repository that supports automatic branch detection (e.g. Git) to the plan at Plan Configuration >> Repositories and make it the default repository by dragging it to the top.
   • You may want to disable the plan first to ensure that no builds happen between actions.
2. Visit Plan Configuration >> Branches and ensure:
   1. Create plan branch is set to Manually
   2. Both Delete plan branch options are unchecked.