Merge branch 'mg/branch-d-m-f'

"git branch -d" (delete) and "git branch -m" (move) learned to
honor "-f" (force) flag; unlike many other subcommands, the way to
force these have been with separate "-D/-M" options, which was
inconsistent.

* mg/branch-d-m-f:
  branch: allow -f with -m and -d
  t3200-branch: test -M

diff --cc builtin/branch.c
Simple merge

diff --cc t/t3200-branch.sh
Simple merge