Use correct field names with addExtensionUpdate

The second parameter to addField is the name of the field being
added.  This patch updates two of those calls to use the same
column name specified in the patch file.

This was noticed because beta labs was trying to re-apply the
patches:

https://integration.wikimedia.org/ci/view/Beta/job/beta-update-databases-eqiad/label=deployment-bastion-eqiad,wikidb=aawiki/3304/console

Change-Id: I5e453069f8edbb871a22ce3d32119a7a398246e3
Merge "Use correct field names with addExtensionUpdate"