venv/activate uses zsh-specific syntax

[prez]

I'm using the yash shell, which is strictly POSIX-compliant and errors out on . .venv/bin/activate.

The snippet using a zsh-specific extension is SCRIPT_PATH="${(%):-%x}" in line 34.

Please take a look at the original issue (I filed this with yash at first) for some context and a potential fix: magicant/yash#62

Thank you.

[notatallshaw]

Fix was reverted