Correct namespaces in fast_scan.h
Correct namespaces in fast_scan.h

marksantos/thrust,sarvex/thrust,thvasilo/thrust,thvasilo/thrust,arnabgho/thrust,thvasilo/thrust,xiongzhanblake/thrust,arnabgho/thrust,GrimDerp/thrust,egaburov/thrust,sdalton1/thrust,egaburov/thrust,xiongzhanblake/thrust_src,GrimDerp/thrust,dachziegel/thrust,marksantos/thrust,dachziegel/thrust,marksantos/thrust,egaburov/thrust,Ricardo666666/thrust,mohamed-ali/thrust,xiongzhanblake/thrust,dachziegel/thrust,arnabgho/thrust,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,thrust/thrust,zeryx/thrust,mohamed-ali/thrust,mohamed-ali/thrust,sarvex/thrust,raygit/thrust,Ricardo666666/thrust,xiongzhanblake/thrust,Ricardo666666/thrust,thrust/thrust,sdalton1/thrust,sarvex/thrust,jaredhoberock/thrust,thrust/thrust,raygit/thrust,raygit/thrust,xiongzhanblake/thrust_src,zhenglaizhang/thrust,xiongzhanblake/thrust_src,sdalton1/thrust,thrust/thrust,GrimDerp/thrust,thrust/thrust,zeryx/thrust,zhenglaizhang/thrust,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,zhenglaizhang/thrust,jaredhoberock/thrust,zeryx/thrust