Build and use osmo-bsc_mgcp from openbsc.git instead of osmo-mgw.git

In osmo-mgw.git 31b4729f2731c747b8b33c4646dd5ade2ace29bc, osmo-bsc_mgcp
was dropped and the one from openbsc.git must be used.

Change-Id: Ib1c46baf4d36ab18f8064a2234a0ba28a1e7d2c2
diff --git a/contrib/jenkins-build-osmo-nitb.sh b/contrib/jenkins-build-osmo-nitb.sh
index ef55259..1e3ecc6 100755
--- a/contrib/jenkins-build-osmo-nitb.sh
+++ b/contrib/jenkins-build-osmo-nitb.sh
@@ -12,4 +12,4 @@
 build_repo libosmo-sccp
 build_repo openbsc --enable-smpp --enable-osmo-bsc --enable-nat
 
-create_bin_tgz osmo-nitb
+create_bin_tgz "osmo-nitb osmo-bsc_mgcp"