The expected value of FileBackendGroup::config()['srvCache'] was being
obtained from MediaWikiServices::getLocalServerObjectCache(), but the
class actually used ObjectCache::getLocalServerInstance( 'hash' ). It
happens these are often the same, so it passed the gate-and-submit jobs,
but it's causing failures on Travis CI.
Follow-up to bd2a439502, which added the failing test. Thanks to
Krinkle for pointing out the failures on CI.
Change-Id: I17651766f4ee2752dfcae9574d2538269dec4ebe
100% coverage except for one bit of the code that I didn't understand.
Unit tests to come, together with rewrite as a service.
Change-Id: Ib01758d994a9e5587a4fcb5edc3d80010ef05615
