Fix for SmartDataCenter list_machines tag logic.

gistfile1.py

from fabric.api import env

def list_machines(*args, **kwargs):
    """
    Wrapper for listing machines which match every tag.  The current api behavior
    is to return a list for any matching tags.
    """
    tags = kwargs.get('tags')
    lol_machines = [] # list of sets of machines
    for key, value in tags.iteritems():
        kwargs['tags'] = { key: value, }
        lol_machines.append(set(env.sdc.machines(*args, **kwargs)))
        if len(lol_machines[-1]) == 0:
            break
    return list(set.intersection(*lol_machines))