Travis: attempting to fix a test failure for WP 3.7 + PHP 5.6.

We had a similar fix in for PHP, this change makes that comparision a little more general so we don't run into this problem in the future.

See r9237 and https://travis-ci.org/buddypress/BuddyPress/jobs/44511661

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9238 cdf35c40-ae34-48e0-9cc9-0c9da1808c22