driver: Followup to last: make the value more unique.
driver: Followup to last: make the value more unique.

Part of issue #305.

joshuarubin/dotfiles,x-way/zsh-syntax-highlighting,x-way/zsh-syntax-highlighting,joshuarubin/dotfiles,phy1729/zsh-syntax-highlighting,m0vie/zsh-syntax-highlighting,danielshahaf/zsh-syntax-highlighting-debian,joshuarubin/dotfiles,P71/zsh-syntax-highlighting,zsh-users/zsh-syntax-highlighting,danielshahaf/zsh-syntax-highlighting,danielshahaf/zsh-syntax-highlighting-debian,m0vie/zsh-syntax-highlighting,stuha/wbr-zsh,phy1729/zsh-syntax-highlighting,psprint/zsh-syntax-highlighting,joshuarubin/dotfiles,P71/zsh-syntax-highlighting,danielshahaf/zsh-syntax-highlighting,psprint/zsh-syntax-highlighting,zsh-users/zsh-syntax-highlighting