Avoid creating unnecessary empty ~/.zshrc

* This gets moved to `~/.zshrc.pre-oh-my-zsh` and replaced w/ a new
  `~/.zshrc` from the Oh My Zsh template
* https://github.com/ohmyzsh/ohmyzsh/blob/d23d3ea69fdb839088e6e5589557cce77b34aaf8/tools/install.sh#L332

Author: dskecse

mac

@@ -12,10 +12,6 @@ trap 'ret=$?; test $ret -ne 0 && printf "failed\n\n" >&2; exit $ret' EXIT
 
 set -e
 
-if [ ! -f "$HOME/.zshrc" ]; then
-  touch "$HOME/.zshrc"
-fi
-
 # Determine Homebrew prefix
 arch="$(uname -m)" # used to be x86_64, now arm64
 if [ "$arch" = "arm64" ]; then