Updated mediawiki/extensions
Project: mediawiki/extensions/Flow  f8ce52a2f26c4aac1918dbab0d5a4602d8ad0997

Check error property exists before access

When receiving a timeout result will be unpopulated and
result.error.prev_revision will throw a TypeError.

Change-Id: Ia81f56dabdb92ee9455f44d320a939b09fcac247