Fix ARC precheck warnings in EXTProtocolCategory
Fix ARC precheck warnings in EXTProtocolCategory

sanojnambiar/libextobjc,liuruxian/libextobjc,bboyesc/libextobjc,telly/libextobjc,goodheart/libextobjc,sandyway/libextobjc,jiakai-lian/libextobjc,KBvsMJ/libextobjc,WPDreamMelody/libextobjc,sunfei/libextobjc,kolyuchiy/libextobjc