python::virtualenv does not accept the string 'pip' as per the documentation

[jeroenjacobs79]

according to init.pp:

[*virtualenv*]
Install python-virtualenv. Default: false, also accepts 'pip' which will
install latest virtualenv from pip rather than package manager

this is incorrect however. setting virtualenv => 'pip' will result in an error:

Example config:

class { 'python':
    version    => '3.4',
    pip        => true,
    dev        => true,
    virtualenv => 'pip',
}

This results in the following error:

=> default: Error: "pip" is not a boolean.  It looks to be a String at /tmp/vagrant-puppet/modules-07dad0bb873a0b6e1fde1b335ada575f/python/manifests/init.pp:82 on node

Please take note of the fact that is says "pip is not a boolean", not "virtualenv is not a boolean"