ISPN-4631 Make sure test servers are shut down before/after tests

https://issues.jboss.org/browse/ISPN-4631
yes, `stopJoiningNodes()` is executed even if previous tests fails (for sure I tried it with failing assert or throwing an exception in previous test).

As for stopping container, in this case the servers needs to be stopped manually as I used them only as an `@ArquillianResource`, so the Arquillian injects an instance into the field, but doesn't do any other action with it. The main reason is that for Kerberos tests Kerberos server has to be started before servers start and when I used Arquillian for managing servers, it started them before Kerberos server in `@BeforeClass` method.

Tests now passing on the master, but some time there was one [random failure](http://ci.infinispan.org/viewLog.html?buildId=14292&buildTypeId=bt8&tab=buildResultsDiv) cause by connection timeout. Not sure what actually caused it.