Summary: Oops, when regexing start->left/right end->left/right I did not take into account flex-start and flex-end. Easiest solution is to regex back flex-left and flex-right into their correct values.
Reviewed By: lucasr
Differential Revision: D3930244
fbshipit-source-id: 20742cbc8e5f23af694e14584c7c3df89526876e