Updated mediawiki/extensions
Project: mediawiki/extensions/Flow  4805026ac3f61fc6a645840372c170e1a6cbfcfb

API: Call dieUsage() on $this, not $this->getResult()

While this will likely change the error codes being returned, I don't
see anything in the JS that checks them.

Change-Id: I86ca37d64cc3f7086d3babb41f9e91e760178984