[FIXED JENKINS-31068] Monitor does not detect when Tomcat URL encoding...

[FIXED JENKINS-31068] Monitor does not detect when Tomcat URL encoding parameter rejects forward slashes in URL  (#2977)

* Fixing JENKINS-31068

* backing out changes--they don't fully work

* Saving progress so that I can revert to an earlier version for tests

* So, pretty exhaustive testing yields that these modifications have the same behavior as the previous versions

* [FIX JENKINS-31068] Adding wiki reference to error message.  Adding trailing slash to URL

* [FIX JENKINS-31068] It looks like different versions of Tomcat and Apache HTTP handle this case differently. Really, the best we can do is check to see if the test method was not hit and passed correctly--if we hit it, we get more information on the configuration error.  If we don't, we just refer them to a general wiki page

core/src/main/resources/hudson/diagnosis/ReverseProxySetupMonitor/message.jelly

@@ -27,7 +27,9 @@ THE SOFTWARE.
   <script>
     var checkAjax=new Ajax.Request('${rootURL}/${it.url}/test', {
         onComplete : function(transport) {
-          if (transport.status==0 || transport.status==404) {
+          if (transport.status != 200) {
+          
+            
             // redirect failed. Unfortunately, according to the spec http://www.w3.org/TR/XMLHttpRequest/
             // in case of error, we can either get 0 or a failure code
             $$('redirect-error').style.display = "block";