Use a single class to create 'neutron' database

Use a class instead of multiplying 'neutron' database definitions.
The class 'system.galera.server.database.neutron' will be included
only once for a node that avoids database definitions dublication.

Change-Id: Ibf318200a7cf83fe3bd00c3ca265ed3bcb989811
Closes-Bug: https://mirantis.jira.com/browse/PROD-15066
6 files changed