benchmark runner is probably broken

[tserong]

srv/modules/runners/benchmark.py does this:

    master_minion = local_client.cmd(
        'I@roles:master', 'pillar.get',
        ['master_minion'], expr_form='compound').items()[0][1]

...but we don't set master_minion in the pillar data anymore. This needs to be changed to something like master_minion = __salt__['master.minion']()