tree 70dfd5c49bc2cbcc4fcdf74ab13ffc9f03bf2767
parent 700f0aff24d9b292f24d802c3af3b5c1705193c5
author Carlos Martín Nieto <cmn@dwim.me> 1454998646 +0100
committer Carlos Martín Nieto <cmn@dwim.me> 1454998646 +0100

commit: also match the first header field when searching

We were searching only past the first header field, which meant we were
unable to find e.g. `tree` which is the first field.

While here, make sure to set an error message in case we cannot find the
field.