Don't require ChocolateyInstall environment variable

[bnason-nf]

The extension currently identifies the location of the chocolatey install by looking at process.env.ChocolateyInstall. If that variable isn't set, it fails with the message "Chocolatey is not installed", even if it is installed and choco is in the path. It would be nice if it could instead just attempt to execute the choco command to see if it's in the path, or at least as a fallback if the environment variable isn't set. If this isn't desirable for some reason, maybe the error message could be improved to indicate that the environment variable needs to be set.

Thanks,
Benbuck

[JPRuskin]

That makes sense!

It looks like adding a bit of extra handling after checking process.env.ChocolateyInstall should make it more resilient - and there was a TODO there, anyway.