HNBGW_Tests: use realistic codec name and payload type in MGCP

When we respond to the MGCP requests from OsmoHNBGW, we use codec name
"FOO" and payload type 23 in the SDP part of the response. This is
obviously an invalid codec and osmo-mgcp-client will not tolerate this
anymore. Let's use a more realistic payload type and codec name, like
112 and "VND.3GPP.IUFP"

Change-Id: Ib53ff7a878087b497e6ff27f786c9ab1297f3d5f
diff --git a/hnbgw/HNBGW_Tests.ttcn b/hnbgw/HNBGW_Tests.ttcn
index e5f227e..f0b5cfe 100644
--- a/hnbgw/HNBGW_Tests.ttcn
+++ b/hnbgw/HNBGW_Tests.ttcn
@@ -165,8 +165,8 @@
 		mgw_rtp_port := 20000,
 		mgcp_connection_id := '22222'H
 	},
-	rtp_payload_type := 23,
-	rtp_sdp_format := "FOO",
+	rtp_payload_type := 112,
+	rtp_sdp_format := "VND.3GPP.IUFP",
 	hnb_rtp_ip := "127.1.1.1",
 	hnb_rtp_port := 10001,
 	cn_rtp_ip := "127.1.3.1",