Reset RevWalk before calling refControl.canCreate()

The internals of IncludedInResolver reuse the existing RevWalk but
carry the UNINTERESTING flag. Within CreateBranch in particular, this
flag may already be set on some commits.

Document this restriction on canCreate.

Change-Id: I5ec75a2bdd079edb5aa21bca3bd3dc33e5c3a0f9
3 files changed