add spec_helper error if probe models not in test db
add spec_helper error if probe models not in test db

Loading probe configurations from the fixtures in 
config/probe_configurations is now part of db:test:prepare

Make sure the error messages are clear.
concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse