Creates the virtual environment and installs PIP only into the
    virtual environment

def create_virtualenv(venv=VENV, install_pip=False):
    """Creates the virtual environment and installs PIP only into the
    virtual environment
    """
    print 'Creating venv...',

    install = ['virtualenv', '-q', venv]
    run_command(install)

    print 'done.'
    print 'Installing pip in virtualenv...',
    if install_pip and \
            not run_command(['tools/with_venv.sh', 'easy_install',
                             'pip>1.0']):
        die("Failed to install pip.")
    print 'done.'