Update - add support to configure plugins via config file

Pull in changes from:
  voxpupuli/puppet-rabbitmq#777

This allow us to configure plugins using the config file
(/etc/rabbitmq/enabled_plugins) and makes it possible to
enable the rabbitmq_management plugin without also
downloading and installing rabbitmqadmin.

Change-Id: I6c35eec19407d77f96cacd7094580198215adc24
Related-Bug: #1815675

puppet-rabbitmq.spec

@@ -1,6 +1,6 @@
 %{!?upstream_version: %global upstream_version %{commit}}
 %define upstream_name puppet-rabbitmq
-%global commit 837d556a1a817f78f4e92b80643b8d43ff437f46
+%global commit 48e8723c55d019ad419a7430700d034a6843fa6a
 %global shortcommit %(c=%{commit}; echo ${c:0:7})
 # DO NOT REMOVE ALPHATAG
 %global alphatag .%{shortcommit}git