Fix Flow issue in RelayContainer
Fix Flow issue in RelayContainer

Summary:
This is pretty ugly, but works around the Flow issue, which is currently breaking open source CI runs (eg. see [[https://travis-ci.org/facebook/relay/jobs/125034679 | this run]] for an example).

The error is coming from some internal product code using React's stateless functional components. I had to rejig the code a bit to make Flow accept it.

Reviewed By: josephsavona

Differential Revision: D3213655

fb-gh-sync-id: c414016bf3405f4d90345892bfa7741193ce58af
fbshipit-source-id: c414016bf3405f4d90345892bfa7741193ce58af

kassens/relay,gabelevi/relay,wincent/relay,josephsavona/relay,kassens/relay,dbslone/relay,dbslone/relay,facebook/relay,rosskevin/relay,voideanvalue/relay,voideanvalue/relay,mroch/relay,iamchenxin/relay,gabelevi/relay,kassens/relay,iamchenxin/relay,xuorig/relay,xuorig/relay,chirag04/relay,zpao/relay,zpao/relay,voideanvalue/relay,mroch/relay,yungsters/relay,facebook/relay,voideanvalue/relay,cpojer/relay,wincent/relay,cpojer/relay,iamchenxin/relay,xuorig/relay,atxwebs/relay,wincent/relay,apalm/relay,josephsavona/relay,kassens/relay,chirag04/relay,wincent/relay,mroch/relay,gabelevi/relay,cpojer/relay,chentsulin/relay,atxwebs/relay,atxwebs/relay,zpao/relay,apalm/relay,xuorig/relay,xuorig/relay,freiksenet/relay,facebook/relay,chentsulin/relay,wincent/relay,atxwebs/relay,voideanvalue/relay,iamchenxin/relay,cpojer/relay,benjaminogles/relay,kassens/relay,freiksenet/relay,facebook/relay,voideanvalue/relay,xuorig/relay,chentsulin/relay,wincent/relay,yungsters/relay,apalm/relay,freiksenet/relay,facebook/relay,yungsters/relay,facebook/relay,benjaminogles/relay,rosskevin/relay,josephsavona/relay,benjaminogles/relay,kassens/relay,chirag04/relay