(7.0.z) Add log message indicating disabled <distributable></distributable> flag from web-fragments

If a web-fragment doesn't have distributable set, then replication is not enabled. This happens silently so it may be confusing to some users that are expecting replication to be enabled when they have set <distributable/> in their WEB-INF/web.xml.

Other third party libraries they included may have web-fragments without distributable set so it'd be nice to log a notification when this happens so that users are easily informed why replication was not enabled as they may have expected.