Fix benign epmd@0.0.0.0.socket failure

* The restart loop for rabbitmq-server can trigger socket activation
  of epmd without rabbitmq-server running. This can lead to 'systemctl
  status' reporting 'State: degraded' with no simple way to reset to
  'State: running'.
* It's important to note that this socket activation failure is benign
  and is not an indicator of system failure.

Change-Id: Iede4f5ebeffb59644dee4a17b6331b3cdd04d146
Signed-off-by: Jan Gutter <jan.gutter@netronome.com>

lib/rpc_backend

@@ -66,7 +66,12 @@ EOF
             sudo systemctl restart epmd.socket epmd.service
         fi
         if is_fedora || is_suse; then
-            sudo systemctl enable rabbitmq-server
+            # NOTE(jangutter): If rabbitmq is not running (as in a fresh
+            # install) then rabbit_setuser triggers epmd@0.0.0.0.socket with
+            # socket activation. This fails the first time and does not get
+            # cleared. It is benign, but the workaround is to start rabbitmq a
+            # bit earlier for RPM based distros.
+            sudo systemctl --now enable rabbitmq-server
         fi
     fi
 }