Add missing __host__ __device__ to sequential::sort & sequential::sort_by_key.
Add missing __host__ __device__ to sequential::sort & sequential::sort_by_key.

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