Remove meaningless default action name

Before: Get the value of the action=... parameter. If it's undefined
return 'view'. Check if 'view' equals 'ajax'.

After: Get the value of the action=... parameter. If it's undefined
return null. Check if null equals 'ajax'.

Same for both places. The default value 'view' is never used.

Change-Id: I56656218cfb895bffe886919c67ebf3b79d91515
Add and use Title::getOtherPage()

Change-Id: I40a51c14ce07c301c15c6c2128cc18bb12e71103
Merge "Remove meaningless default action name"
Merge "Add and use Title::getOtherPage()"
Localisation updates from https://translatewiki.net.

Change-Id: I1ab91507623ac4c465066d73cc74658b35c8b534
Cleanup DatabaseBase::query implicit transaction code

* Add DatabaseBase::isTransactableQuery() for checking whether a query could
  benefit from being executed in a transaction.

Change-Id: Ie5b116bc726b47c68459e6525a1bb43b96bd9f30