Xcode 9 warnings

[ivulyov90]

I have few warnings in Xcode 9.0.1
It will be nice to fix them

Pods/WYPopoverController/WYPopoverController/WYPopoverController.m:1841:27: This block declaration is not a prototype
Pods/WYPopoverController/WYPopoverController/WYPopoverController.m:2401:30: This block declaration is not a prototype
Pods/WYPopoverController/WYPopoverController/WYPopoverController.m:2413:26: This block declaration is not a prototype