implement channel_enabled?

[logicminds]

The bmc provider for ipmitool needs to query the ipmitool to verify that the channel is enabled.

Currently in the exists? method there is a bug where if the channel is disabled the channel could never be enabled unless one of the network properties changed.

We just need to figure out how to query ipmi to find out if the channel is enabled.

def channel_enabled?
# TODO implement how to look up this info
true
end