maven: remove explicit submodule versions from module pom.xml

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>
Sync: Merge branch 'master' into api_refactoring

Conflicts:
	plugins/network-elements/dns-notifier/pom.xml

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>