rpcserver: only set channel Active=true if added to htlcswitch
rpcserver: only set channel Active=true if added to htlcswitch

For a calls to ListChannels we now only set the
ActiveChannel.Active=true if the link is found by the
htlcswitch. This is done to be able to make it possible
to tell if a newly opened channel has been added to
the htlcswitch, such that we can synchronize on this
during tests before we attempt to close the  channel.

LightningNetwork/lnd,aakselrod/lnd,LightningNetwork/lnd,aakselrod/lnd