Commit
84f2d35cea44009ae199af492490682c51f3cb04
by Vadim Yanitskiyosmo-ns-master: drop python3-osmopy-utils / --enable-external-tests
--enable-external-tests requires python3-osmopy-utils, however this
package is no longer available for debian:10. We're not running
tests, so it's not really needed. Removing it fixes ttcn3-ns-test-fr.
Change-Id: I342099be87175dfe189a8906b53ee26328c0a417