Combine text and ID update fields

bumped to version 1.8.0 (requires MediaWiki with fixed bug 50078)

Reduce the number of expensive database queries performed while merging
by combining the updates of text fields with their corresponding ID fields.

This fix requires a MediaWiki core after 20130525 with fixed bug 50078
in Database::delete (merged in https://gerrit.wikimedia.org/r/#/c/70423/ )

Bug: 49517
Bug: 49520
Change-Id: Ibb36ef49e99246e502835f51ab6776422b62438d
Merge "Combine text and ID update fields"