openbsc: Decrease the version number of MNCC to 2 again

Currently OpenBSC and LCR are not compatible with each other.
So far we have only included patches that add new defines and
do not change the wire format of messages. Just revert it so
we can have LCR talk to OpenBSC

recipes-osmocom/openbsc/openbsc/revert-mncc-version.patch

@@ -0,0 +1,19 @@
+OpenBSC has bumped the version from 2 to 4 but only introduced
+new defines so the actual wire protocol has not been changed
+yet. This is why we can just turn the version back. At least I
+hope so.
+
+
+Index: openbsc/include/openbsc/mncc.h
+===================================================================
+--- openbsc.orig/include/openbsc/mncc.h
++++ openbsc/include/openbsc/mncc.h
+@@ -163,7 +163,7 @@ struct gsm_data_frame {
+ 	unsigned char	data[0];
+ };
+ 
+-#define MNCC_SOCK_VERSION	4
++#define MNCC_SOCK_VERSION	2
+ struct gsm_mncc_hello {
+ 	uint32_t	msg_type;
+ 	uint32_t	version;

recipes-osmocom/openbsc/openbsc_git.bb

@@ -1,9 +1,10 @@
 require ${PN}.inc
 
 PV = "0.13.0+gitr${SRCPV}"
-PR = "${INC_PR}.3"
+PR = "${INC_PR}.4"
 
 SRCREV = "8a158bb1ea36d0f88da18d0f034884b30f09fda2"
-SRC_URI += "git://git.osmocom.org/openbsc.git;protocol=git"
+SRC_URI += "git://git.osmocom.org/openbsc.git;protocol=git \
+    file://revert-mncc-version.patch"
 
 S = "${WORKDIR}/git/openbsc"