add addition note about the warning WFLYCLWEBUT0007

spring-resteasy/README-source.adoc

@@ -64,6 +64,13 @@ WARN  [org.jboss.as.ee] (MSC service thread 1-5) WFLYEE0007: Not installing opti
 WARN  [org.jboss.as.ee] (MSC service thread 1-5) WFLYEE0007: Not installing optional component org.springframework.web.context.request.async.StandardServletAsyncWebRequest due to an exception (enable DEBUG log level to see the cause)
 ----
 
+This warning can be ignored too:
+
+[source,options="nowrap"]
+----
+WARN [org.wildfly.clustering.web.undertow] (ServerService Thread Pool -- 32) WFLYCLWEBUT0007: No routing provider found for default-server; using legacy provider based on static configuration
+----
+
 // Server Distribution Testing
 include::../shared-doc/run-integration-tests-with-server-distribution.adoc[leveloffset=+1]
 // Undeploy the Quickstart