Allows modeshape sequencer tests to be executed through mvn successfully

* The modeshape.lib plugin contains the Sequencer class which uses
  class.forName() in order to load sequencer class specified in modeshape
  repo configuration files.

* The modeshape.lib plugin is not privy to other plugins where the
  sequencers may be defined hence the buddy policy must be employed to
  allow the lib plugin access to the other plugins' classpaths.