contrib: Disable doxygen doc generation

The --disable-doxygen was recently added to libosmocore and
libosmo-netif. No need to manually remove documentation anymore.

Change-Id: I3ca3dd1c115fc6784e4dc26a5ff5bf35d65b4e22
diff --git a/contrib/jenkins-build-osmo-nitb.sh b/contrib/jenkins-build-osmo-nitb.sh
index 76fd6ba..2f26a20 100755
--- a/contrib/jenkins-build-osmo-nitb.sh
+++ b/contrib/jenkins-build-osmo-nitb.sh
@@ -4,9 +4,9 @@
 name="osmo-nitb"
 . "$(dirname "$0")/jenkins-build-common.sh"
 
-build_repo libosmocore
+build_repo libosmocore --disable-doxygen
 build_repo libosmo-abis
-build_repo libosmo-netif
+build_repo libosmo-netif --disable-doxygen
 build_repo openggsn
 build_repo libsmpp34
 build_repo libosmo-sccp