whereis lookup logic is wrong

[techtonik]

The package should not fallback on whereis if which failed on Linux. See webdriverio/selenium-standalone#96 for the example of mislocating java binary by trusting whereis.

See https://superuser.com/questions/40301/which-whereis-differences for the explanation of whereis command. It should come with additional checks to get binaries correctly.

[vvo]

I am happy to take a PR on this @techtonik

[techtonik]

Not sure it will happen any time soon. As I don't code in JavaScript, there is bigger issue with understanding the whole Gratipay JS testing toolchai, and it will just take more time for me than for somebody who knows how npm works and deal with it daily.

[vvo]

@techtonik I think using https://github.com/isaacs/node-which is the way to go