Martin von Zweigbergk <martinvonz@google.com> [Wed, 17 May 2017 09:43:50 -0700] rev 32312
match: remove ispartial()
The function was added in d1d69ca78883 (match: add match.ispartial(),
2015-05-15) for use by narrowhg, but narrowhg never ended up needing
it.