Add beaker tests.

This just sets up a very basic framework for beaker-rspec acceptance
tests for rabbitmq, and tests that class { 'rabbitmq': } and class {
'rabbitmq::server': } can be applied without errors.
remove $manage_service (unused); should be using $service_manage
Fix rabbitmq::server to not use rabbitmq::manage_service anymore.

Also, deprecated rabbitmq::server::manage_service in favor of
rabbitmq::server::service_manage.
Updating Rakefile as we're moving away from rspec-system.
$erlang_manage was removed in https://github.com/puppetlabs/puppetlabs-rabbitmq/pull/135
Merge pull request #185 from mhaskel/cleanup_service_management

Cleanup service management
Merge pull request #186 from mhaskel/doc_fix

$erlang_manage was removed in https://github.com/puppetlabs/puppetlabs-r...
Got rid of old system tests.

Functionality all moved to acceptance tests and beaker-rspec.  Nodesets added for trusty and saucy.
Merge pull request #187 from mhaskel/acceptance_tests

Got rid of old system tests.