mgcp/test: Add test case using the fmtp_extra info

Add tests setting the fmtp_extra field to check the response
generation. This triggers a bug found by Coverity.

Addresses: Coverity CID 1220873
Sponsored-by: On-Waves ehf
diff --git a/openbsc/tests/mgcp/mgcp_test.ok b/openbsc/tests/mgcp/mgcp_test.ok
index 7301a81..6c5a6bc 100644
--- a/openbsc/tests/mgcp/mgcp_test.ok
+++ b/openbsc/tests/mgcp/mgcp_test.ok
@@ -75,6 +75,44 @@
 Requested packetization period not set
 Connection mode: 0: NONE
 Testing CRCX
+CRCX failed '200 2 OK

+I: 3
+
+v=0

+o=- 3 23 IN IP4 0.0.0.0

+c=IN IP4 0.0.0.0

+t=0 0

+m=audio 0 RTP/AVP 126

+a=rtpmap:126 AMR/8000

+a=rtpmap:126 AMR/8000

+a=ptime:20

+'
+Dummy packets: 1
+Detected packet duration: 40
+Requested packetetization period: 20-20
+Connection mode: 1: RECV
+Testing MDCX3
+MDCX3 failed '200 18983215 OK

+I: 3
+
+v=0

+o=- 3 23 IN IP4 0.0.0.0

+c=IN IP4 0.0.0.0

+t=0 0

+m=audio 0 RTP/AVP 126

+a=rtpmap:126 AMR/8000

+a=rtpmap:126 AMR/8000

+a=ptime:20

+'
+Dummy packets: 1
+Packet duration not set
+Requested packetization period not set
+Connection mode not set
+Testing DLCX
+Detected packet duration: 20
+Requested packetization period not set
+Connection mode: 0: NONE
+Testing CRCX
 Re-transmitting CRCX
 Testing RQNT1
 Re-transmitting RQNT1