Summary:
Fix for #413. This was a hangover from a previous attept to fix other align-content problems.
Closes https://github.com/facebook/yoga/pull/417

Reviewed By: astreet

Differential Revision: D4604727

Pulled By: emilsjolander

fbshipit-source-id: 92fd31a385d8182c6b201c891d5ae478372d525d