MGCP_Test: fix TC_dlcx_wildcarded

When the final condition of the testcase is verified through statsd,
there may be still (invalid) data from a previous measurement in the
statsd pipeline, querying the stats once before verifying the actual
stats fixes the problem.

Change-Id: I5fe18e433b32c364778b515ed37fcbcf443b3cb3
Related: OS#5572
diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index 60f955f..0242db9 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -1118,8 +1118,14 @@
 		cmd := ts_DLCX(get_next_trans_id(), ep);
 		mgcp_transceive_mgw(cmd, rtmpl);
 
-		/* The second interval must resturn a result with 0 endpoints in use. */
-		f_sleep(1.0)
+		/* Query a the statsd once to ensure that intermediate results are pulled from the
+		 * pipeline. The second query (below) will return the actual result. */
+		expect := {
+			{ name := "TTCN3.trunk.virtual-0.common.endpoints.used", mtype := "g", min := 0, max := n_endpoints}
+		};
+		f_statsd_expect(expect);
+
+		/* The second query must resturn a result with 0 endpoints in use. */
 		expect := {
 			{ name := "TTCN3.trunk.virtual-0.common.endpoints.used", mtype := "g", min := 0, max := 0}
 		};