BZ #1147077 - Explicitly require rabbitmq service before setting HA policy

https://bugzilla.redhat.com/show_bug.cgi?id=1147077

PR erratum for #372.  Require the class instead of the service
resource, since the service resource does not exist after the first
run due to the service being unmanaged.
Merge pull request #374 from jeckersb/require-rabbitmq-service

BZ #1147077 - Explicitly require rabbitmq service before setting HA policy