Updated mediawiki/extensions
Project: mediawiki/extensions/Flow  196ce994cfc7420a287fbcb3700d17f02bf5760a

Use addError() to add errors, instead of adding to array ourselves

The important thing here is that additional information can now be saved, which
will be necessary later to deal with specific errors.

E.g. edit conflicts will need to know the id of the revision that has been
inserted most recently, so we'll have to expose that along with the error msg.

Change-Id: I039d4a61cd3f6a5f9a3b64f96427774f20076bdb