Ignore height as well as width for framed images.

This makes the PHP parser behavior consistent with the specification at
https://www.mediawiki.org/wiki/Help:Images#Size_and_frame which says:
"An image with frame always ignores the size specification."

This is actually a fix to File::getUnscaledThumb() -- which didn't
actually return an unscaled thumb if the 'height' parameter was set.

Bug: 62258
Change-Id: I0ce295a4681042c446314945da5f811448b44fe6
Merge "Ignore height as well as width for framed images."