Merge branch 'mh/update-ref-errors'

Error handling in the codepaths that updates refs has been
improved.

* mh/update-ref-errors:
  lock_ref_for_update(): avoid a symref resolution
  lock_ref_for_update(): make error handling more uniform
  t1404: add more tests of update-ref error handling
  t1404: document function test_update_rejected
  t1404: remove "prefix" argument to test_update_rejected
  t1404: rename file to t1404-update-ref-errors.sh

diff --cc refs/files-backend.c
Simple merge