BSC_Tests_VAMOS: fix TC_chan_act_to_vamos: deactivate lchan

Keeping the logical channel active may affect test cases executed
after TC_chan_act_to_vamos.  Clean up after the test to avoid that.

Change-Id: Id0e3fb6a2f7e97ef854bff95adbc715d6f41f069
Related: OS#5444

bsc/BSC_Tests_VAMOS.ttcn

@@ -264,6 +264,8 @@ testcase TC_chan_act_to_vamos() runs on test_CT {
 	f_sleep(1.0);
 	f_lchan_ensure_established(BSCVTY, 0, 0, chan_nr);
 
+	f_vty_transceive(BSCVTY, "bts 0 trx 0 timeslot 1 sub-slot 0 deactivate");
+
 	f_shutdown_helper();
 }