mlmmj: Fix invalid mailman entry and update dbs

[noqqe]

Hi,

two things are contained in this PR that are somehow related.

Invalid Mailman Command

There is a "$domain mailman:" entry generated on creation which ends up in a warning and messages that cannot be delivered due to "mail transport unavailables"

Sep 16 09:22:05 nixe.k4cg.org postfix/qmgr[23117]: warning: connect to transport private/mailman: No such file or directory
Sep 16 09:22:05 nixe.k4cg.org postfix/error[23227]: 8973C8975E6C: to=<$mailaddr>, relay=none, delay=0.03, delays=0.02/0/0/0, dsn=4.3.0, status=deferred (mail transport unavailable)

virtual and transports databases are not updated

when new content is coming (or changed) the belonging virtuals.db and transports.db are not being updated by module

warning: database /var/lib/mlmmj/transports.db is older than source file /var/lib/mlmmj/transports

Both of these errors are fixed in the PR

[edwtjo]

Thanks!