Add fcrepo-metrics test dependency.

This should not be necessary, but the dependency loading in Jenkins
  indicates that fcrepo-metrics is not always loaded in time.
http://jenkins.fcrepo.org/job/fcrepo-camel/org.fcrepo.camel$fcrepo-camel/21/testReport/junit/org.fcrepo.camel.integration/FedoraFileIT/testFile/