Do not call chpwd hooks in setup.zsh

By default, cd'ing on zsh calls the shell function `chpwd`. This is commonly used for things like showing the current directory in the title terminal by printing a string with some escape codes, but this breaks `_CATKIN_SETUP_DIR`. `-q` disables the chpwd hooks.

The zshbuiltins(1) man page writes about -q: "If  the -q (quiet) option is specified, the hook function chpwd and the functions in the array chpwd_functions are not called. This is useful for calls to cd that do not change the environment seen by an interactive user."