Update PHP version in php manifest to 5.4.25

5.4.24-1+sury.org~precise+1 is no longer available in the oldstable PPA.  This version - 5.4.25-1+sury.org~precise+2 - may not perfectly mirror wp.com, but at least it can be installed.
Merge pull request #136 from ziz/fix-php

Update PHP version in php manifest to 5.4.25