Merge branch 'cm/branch-delete-error-message-update'

"git branch -d origin/master" would say "no such branch", but it is
likely a missed "-r" if refs/remotes/origin/master exists.  The
command has been taught to give such a hint in its error message.

* cm/branch-delete-error-message-update:
  branch: improve error log on branch not found by checking remotes refs

diff --cc builtin/branch.c
Simple merge