Use shorter URL for RabbitMQ documentation

As suggested in
https://github.com/puppetlabs/puppetlabs-rabbitmq/pull/225.

Author: mattbostock

lib/puppet/provider/rabbitmq_user_permissions/rabbitmqctl.rb

@@ -104,7 +104,7 @@ def set_permissions
   end
 
   def self.strip_backslashes(string)
-    # See: https://github.com/rabbitmq/rabbitmq-server/blob/16418a9488e15c4d8ef3bfa9fce69190fb8ec796/docs/rabbitmqctl.1.pod#output-escaping
+    # See: https://github.com/rabbitmq/rabbitmq-server/blob/v1_7/docs/rabbitmqctl.1.pod#output-escaping
     string.gsub(/\\\\/, '\\')
   end