Put in fix for when which command returns extra information

I was having problems using GVM on my local machine.  I'm using zsh running on Arch Linux.  The issue was that the which command outputs some human-readable information before the path.  So the which output on my machine looks like this:

sort is /usr/bin/sort

This patch might not be the best way to fix this issue, but testing it on my end it looked a little safer anyway.