'Force a new connection to ``key`` host string.'

def connect(self, key):

    from fabric.state import env
    (user, host, port) = normalize(key)
    key = normalize_to_string(key)
    seek_gateway = True
    if env.gateway:
        seek_gateway = (normalize_to_string(env.gateway) != key)
    self[key] = connect(user, host, port, cache=self, seek_gateway=seek_gateway)
