jenkins: fix build of --enable-iu: use osmo-iuh tag 'old_sua'

We are building with libosmo-sccp tag 'old_sua' until the new sigtran has
been applied. Since osmo-iuh commit
  0f88c110093935305143987638e46dc6db304a3e
  "migrate osmo-hnbgw to libosmo-sigtran's SCCP/M3UA"
osmo-iuh requires libosmo-sccp master. A similar 'old_sua' tag is in place in
osmo-iuh.git, to match libosmo-sccp 'old_sua'. Do that to fix the jenkins
build of --enable-iu.

Change-Id: I70f731db0b74ed48ae6dd713ed4c3247222ef0de
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index 0021947..068ee34 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -19,6 +19,7 @@
 
 if [ "x$IU" = "x--enable-iu" ]; then
 	sccp_branch="old_sua"
+	osmo_iuh_branch="old_sua"
 fi
 
 osmo-build-dep.sh libosmo-abis
@@ -30,7 +31,7 @@
 if [ "x$IU" = "x--enable-iu" ]; then
 	osmo-build-dep.sh libasn1c
 	#osmo-build-dep.sh asn1c aper-prefix # only needed for make regen in osmo-iuh
-	osmo-build-dep.sh osmo-iuh
+	osmo-build-dep.sh osmo-iuh $osmo_iuh_branch
 fi
 
 set +x