Add __pycache__ to .gitignore
Add __pycache__ to .gitignore

Running `make` creates the `src/etc/__pycache__` directory which should
not be checked in.

cmr/cargo,brson/cargo,tshepang/cargo,mark-buer/cargo,AndiDog/cargo,gchp/cargo,tshepang/cargo,cmr/cargo,vojtechkral/cargo,rustyhorde/cargo,vojtechkral/cargo,rust-lang/cargo,achanda/cargo,ThinTim/cargo,gchp/cargo,tsurai/cargo,mark-buer/cargo,blaenk/cargo,durka/cargo,sbeckeriv/cargo,durka/cargo,tsurai/cargo,achanda/cargo,durka/cargo,rust-lang/cargo,mark-buer/cargo,AndiDog/cargo,mark-buer/cargo,cmr/cargo,durka/cargo,rustyhorde/cargo,gchp/cargo,achanda/cargo,vojtechkral/cargo,nipunn1313/cargo,tshepang/cargo,tshepang/cargo,AndiDog/cargo,ThinTim/cargo,nipunn1313/cargo,rust-lang/cargo,blaenk/cargo,achanda/cargo,mark-buer/cargo,vojtechkral/cargo,AndiDog/cargo,tsurai/cargo,sbeckeriv/cargo,eminence/cargo,brson/cargo,blaenk/cargo,ThinTim/cargo,nipunn1313/cargo,eminence/cargo,ThinTim/cargo,brson/cargo,gchp/cargo,gchp/cargo,sbeckeriv/cargo,blaenk/cargo,tsurai/cargo,nipunn1313/cargo,eminence/cargo,brson/cargo,tsurai/cargo,blaenk/cargo,rust-lang/cargo,rustyhorde/cargo,ThinTim/cargo,cmr/cargo,sbeckeriv/cargo,cmr/cargo,eminence/cargo,brson/cargo,AndiDog/cargo,rustyhorde/cargo