Merge branch 'rh/mergetool-regression-fix'

Merge branch 'rh/mergetool-regression-fix'

"git mergetool" without any pathspec on the command line that is
run from a subdirectory became no-op in Git v2.11 by mistake, which
has been fixed.

* rh/mergetool-regression-fix:
  mergetool: fix running in subdir when rerere enabled
  mergetool: take the "-O" out of $orderfile
  t7610: add test case for rerere+mergetool+subdir bug
  t7610: spell 'git reset --hard' consistently
  t7610: don't assume the checked-out commit
  t7610: always work on a test-specific branch
  t7610: delete some now-unnecessary 'git reset --hard' lines
  t7610: run 'git reset --hard' after each test to clean up
  t7610: don't rely on state from previous test
  t7610: use test_when_finished for cleanup tasks
  t7610: move setup code to the 'setup' test case
  t7610: update branch names to match test number
  rev-parse doc: pass "--" to rev-parse in the --prefix example
  .mailmap: record canonical email for Richard Hansen