Fix Neutron DB migration scripts execution logic

The migration scripts should be triggered by neutron-server package
installation, because it's required during upgrade.
Currently neutron-server is installed as a dependency for other packages, so
more strict packages ordering is required.

Change-Id: I5d10ff9df6a37ad807d0d0214f3a6113bd58c08c
Closes-bug: #1361541
Merge "Fix Neutron DB migration scripts execution logic"