legacy: mgcp_protocol: Don't print osmux stats if it is off

Otherwise we get Osmux stats during a session using RTP, which is
confusing.

Forward-ported from openbsc e39e18992a3b966581f06fa632d6342643996aaa.

Change-Id: I9031350242dd37ce255631c20eed33976887faa6
diff --git a/tests/legacy_mgcp/mgcp_test.c b/tests/legacy_mgcp/mgcp_test.c
index a540b5f..1a4513e 100644
--- a/tests/legacy_mgcp/mgcp_test.c
+++ b/tests/legacy_mgcp/mgcp_test.c
@@ -268,7 +268,9 @@
 		 "C: 2\r\n"
 
 #define DLCX_RET "250 7 OK\r\n"			\
-		 "P: PS=0, OS=0, PR=0, OR=0, PL=0, JI=0\r\n" \
+		 "P: PS=0, OS=0, PR=0, OR=0, PL=0, JI=0\r\n"
+
+ #define DLCX_RET_OSMUX DLCX_RET                 \
 		 "X-Osmo-CP: EC TIS=0, TOS=0, TIR=0, TOR=0\r\n"
 
 #define RQNT	 "RQNT 186908780 1@mgw MGCP 1.0\r\n"	\