convert: use branchmap to change default branch in destination (issue3469)...
convert: use branchmap to change default branch in destination (issue3469)
The fix for issue2653 broke the ability to map the default branch of a source
repository to a non-default named branch in the destination repository. Leave
the default behaviour as is, but allow the branch name "None" to be used to map
to a non-default named branch in the destination repository.