Disable RabbitMQ busy-wait for dirty cpu and dirty i/o schedulers

This aligns the defaults with the recommendations from upstream:

https://www.rabbitmq.com/runtime.html#busy-waiting

Change-Id: Ief7fb44f53b55a73d76ef3aa29dcd17194a6fc98

deployment/rabbitmq/rabbitmq-container-puppet.yaml

@@ -76,10 +76,11 @@ parameters:
   RabbitAdditionalErlArgs:
     description:
       Additional parameters passed to the Erlang subsystem. The string
-      needs to be enclosed in quotes twice. We default to +sbwt none
-      in order to have the erlang vm be less busy on spinlocks, but
-      we allow a simple way of overriding it.
-    default: "'+sbwt none'"
+      needs to be enclosed in quotes twice. We default to '+sbwt none
+      +sbwtdcpu none +sbwtdio none' in order to have the erlang vm be
+      less busy on spinlocks, but we allow a simple way of overriding
+      it.
+    default: "'+sbwt none +sbwtdcpu none +sbwtdio none'"
     type: string
   MonitoringSubscriptionRabbitmq:
     default: 'overcloud-rabbitmq'

releasenotes/notes/erl-sbwtdcpu-sbwtdio-b26506a0430480dc.yaml

@@ -0,0 +1,9 @@
+---
+other:
+  - |
+    The default value of the parameter 'RabbitAdditionalErlArgs' was
+    updated to include the new options '+sbwtdcpu none +sbwtdio none'
+    which disables busy-wait for dirty cpu schedulers and dirty i/o
+    schedulers respectively.  This aligns with the flags recommended
+    by RabbitMQ upstream
+    (https://www.rabbitmq.com/runtime.html#busy-waiting).