Update DataObject.php

Documentation fix:

Table at http://api.silverstripe.org/3.1/class-DataObject.html is displaying the data wrong. Current it says "protected A" instead of "protected ValidationResult" as it should be.
Merge pull request #3613 from spekulatius/patch-1

Update DataObject.php
filterAny method comments fixed to reflect actual operation
Merge pull request #3637 from Copperis/method-comment-fix

filterAny method comments fixed to reflect actual operation
Update changelogs
Merge remote-tracking branch 'origin/3.1.7' into 3.1