JMX fix allow multiple Norbert servers in same JVM

This adds the same fixe as 793e164d80b821d04c4be0e21d0da198a6a509de
does, but to a few more places which are used when running as a server.

https://linkedin.jira.com/browse/NOR-12
Merge pull request #14 from stromnet/master

JMX fix allow multiple Norbert servers in same JVM