Merge branch 'jc/maint-ident-missing-human-name'

"git show --format='%ci'" did not give timestamp correctly for
commits created without human readable name on "committer" line.

* jc/maint-ident-missing-human-name:
  split_ident_line(): make best effort when parsing author/committer line

diff --cc builtin/commit.c
Simple merge