Fix bugs in python_bindings CMakeLists.txt
Fix bugs in python_bindings CMakeLists.txt


Former-commit-id: 22b2e698c0476062ecaf28c33699cffe0348b16b
darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide