Martin von Zweigbergk <martinvonz@google.com> [Thu, 02 Aug 2018 14:30:40 -0700] rev 38909
narrow: remove a repo file-cache invalidation
It's unclear why this was needed. All tests pass without it. I asked
Kyle Lippincott (who added the check) and he also doesn't remember
what it was for.
Differential Revision: https://phab.mercurial-scm.org/D4097