Installing chef inside vm via proxy is broken ... again

[jeka]

At some point with refactoring installation on environments with internet access only via proxy broke again.
I think the problem is switching to machine.communicate.tap. Shell invocation is no more login shell and there are no proxy related environment variables set.
Easy fix for me was to force 'sh' to be login shell i.e. 'sh -l' in action/install_chef.rb/install
But maybe there is better solution.

Here are the plugins I am using:
vagrant-omnibus (1.4.1)
vagrant-proxyconf (1.5.0)