<oo-accept-broker> Bug 959164 - Fix mongo test with replica sets

https://bugzilla.redhat.com/show_bug.cgi?id=959164

Fix mongo db tests in oo-accept-broker when using a mongo replica set.

Added a Require for mongodb (the client package) for
openshift-origin-broker-util, otherwise oo-accept-broker fails when the
mongodb host is not the same as the broker.