Add CHANGELOG entry for 1.7.2
Add CHANGELOG entry for 1.7.2

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