bts: Avoid race condition in  TC_pcu_deact_req

When our emulated PCU sends a DEACT.req to the BTS, there is no way
of knowing when exactly that command will have been completed: There is
no confirmation sent in response.

Let's introduce a f_sleep(1.0) to give the BTS sufficient time for
deactivating the channel.

This will make  TC_pcu_deact_req pass reliably.  It currently fails
in about one third of all test executions on jenkins.

Change-Id: Id9a559b8b208a60f71c3eb9a23830e4d2dbc5df9
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index e24356a..b381893 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -4379,7 +4379,9 @@
 
 	/* Send PDCH activate request for known PDCH timeslot */
 	PCU.send(t_SD_PCUIF(g_pcu_conn_id, ts_PCUIF_DEACT_REQ(bts_nr, trx_nr, ts_nr)));
-
+	/* wait for some time as there is no PCUIF_DEACT_RESP or the like, so we don't know
+	 * when it will actually have been executed in the BTS */
+	f_sleep(1.0);
 	PCU.clear;
 	/* we now expect no RTS.req for this timeslot */
 	T.start;