Remove unused gesture recognizer.
Remove unused gesture recognizer.

jianwoo/PSTCollectionView,CorzFree/PSTCollectionView,Kevin775263419/PSTCollectionView,Amnysia/PSTCollectionView,godLoveLucifer/PSTCollectionView,zjh171/PSTCollectionView,StephaneDelcroix/PSTCollectionView,steipete/PSTCollectionView,ba01ei/PSTImprovedCollectionView,niuxinghua/PSTCollectionView,Anish-kumar-dev/PSTCollectionView,zace-yuan/PSTCollectionView,StephaneDelcroix/PSTCollectionView