Added error checking on halide_init_kernels.
Added error checking on halide_init_kernels.


Former-commit-id: 2b4fb66d8cde786cdff896fa1d62db1cd4e42612
darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide