An engine restart sends dis-connect messages for the reverse
port-mapping (after making the connection):
Connect: system:midi_capture_41a56f90 -> ardour:MTC in
Connect: system:capture_1 -> ardour:LTC in
DisConnect: ardour:MTC in -> system:midi_capture_41a56f90
DisConnect: ardour:LTC in -> system:capture_1
This lead to TransportMaster being marked as inactive.
This is likely an issue that should be fixed elsewhere, but in
case of JACK, we likely do not have control over this.
58c5f75fc9