Merge branch 'jc/fix-ref-sorting-parse'

Merge branch 'jc/fix-ref-sorting-parse'

Things like "git -c branch.sort=bogus branch new HEAD", i.e. the
operation modes of the "git branch" command that do not need the
sort key information, no longer errors out by seeing a bogus sort
key.

* jc/fix-ref-sorting-parse:
  for-each-ref: delay parsing of --sort=<atom> options