Beef up Flow typing for RelayMutation props
Beef up Flow typing for RelayMutation props

Summary: Talked to @yungsters and `RelayMutation` should be parameterized on the
type of the props, which are passed in to the constructor. If some props should
be optional, then that should be explicitly annotated.

After making this change to `RelayMutation` I had to update 2 subclasses.

Reviewed By: @yungsters

Differential Revision: D2414238

dbslone/relay,Shopify/relay,chirag04/relay,quazzie/relay,IlyasM/relay,magnus-lycka/relay,kassens/relay,Sandreu/relay,yungsters/relay,magnus-lycka/relay,wincent/relay,wincent/relay,ide/relay,jshanson7/relay,pandoraui/relay,kangkot/relay,u9520107/relay,vjeux/relay,mroch/relay,IlyasM/relay,xuorig/relay,chentsulin/relay,apalm/relay,wangcan2014/relay,u9520107/relay,jeffmo/relay,kangkot/relay,facebook/relay,voideanvalue/relay,tmitchel2/relay,gabelevi/relay,kassens/relay,NevilleS/relay,facebook/relay,atxwebs/relay,wangcan2014/relay,Sandreu/relay,Aweary/relay,TobiasBales/relay,lucasterra/relay,benjaminogles/relay,janusnic/relay,wincent/relay,chirag04/relay,vjeux/relay,iamchenxin/relay,cpojer/relay,xuorig/relay,xymostech/relay,dmfrancisco/relay,vedmalex/relay,wincent/relay,josephsavona/relay,chentsulin/relay,xuorig/relay,zpao/relay,jshanson7/relay,voideanvalue/relay,almasakchabayev/relay,voideanvalue/relay,rosskevin/relay,kangkot/relay,jeffmo/relay,niklasvh/relay,wincent/relay,voideanvalue/relay,wincent/relay,kassens/relay,IlyasM/relayWorking,niklasvh/relay,almasakchabayev/relay,michaelchum/relay,heracek/relay,supriyantomaftuh/relay,yungsters/relay,kassens/relay,venepe/relay,zpao/relay,niklasvh/relay,xuorig/relay,yungsters/relay,mroch/relay,atxwebs/relay,chirag04/relay,cpojer/relay,ide/relay,Shopify/relay,facebook/relay,venepe/relay,beni55/relay,u9520107/relay,quazzie/relay,Aweary/relay,mroch/relay,lucasterra/relay,michaelchum/relay,quazzie/relay,rosskevin/relay,jtthrillson/relay,bneiluj/relay,ide/relay,IlyasM/relayWorking,bneiluj/relay,andimarek/generic-relay,tmitchel2/relay,AnSavvides/relay,voideanvalue/relay,vedmalex/relay,dmfrancisco/relay,venepe/relay,freiksenet/relay,IlyasM/relayWorking,dbslone/relay,apalm/relay,benjaminogles/relay,josephsavona/relay,vedmalex/relay,almasakchabayev/relay,NevilleS/relay,cpojer/relay,cesarandreu/relay,lucasterra/relay,AbhinavJain13/relay,tmitchel2/relay,beni55/relay,jshanson7/relay,supriyantomaftuh/relay,jtthrillson/relay,mcanthony/relay,Shopify/relay,magnus-lycka/relay,michaelchum/relay,josephsavona/relay,atxwebs/relay,heracek/relay,dmfrancisco/relay,janusnic/relay,xuorig/relay,AnSavvides/relay,jtthrillson/relay,benjaminogles/relay,pandoraui/relay,freiksenet/relay,andimarek/generic-relay,Aweary/relay,kassens/relay,cpojer/relay,cesarandreu/relay,freiksenet/relay,bneiluj/relay,forter/generic-relay,chentsulin/relay,xymostech/relay,iamchenxin/relay,gabelevi/relay,xymostech/relay,kassens/relay,mcanthony/relay,wangcan2014/relay,cesarandreu/relay,facebook/relay,gabelevi/relay,iamchenxin/relay,facebook/relay,mcanthony/relay,TobiasBales/relay,voideanvalue/relay,facebook/relay,AnSavvides/relay,atxwebs/relay,apalm/relay,NevilleS/relay,janusnic/relay,beni55/relay,AbhinavJain13/relay,iamchenxin/relay,TobiasBales/relay,heracek/relay,jeffmo/relay,vjeux/relay,zpao/relay,andimarek/generic-relay,xuorig/relay