added a log message so that we can better understand #167.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1147 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/scm/SubversionSCM.java

@@ -370,8 +370,10 @@ public class SubversionSCM extends AbstractCVSFamilySCM {
         // check the corresponding remote revision
         for (SvnInfo localInfo : wsRev.values()) {
             SvnInfo remoteInfo = SvnInfo.parse(localInfo.url,env,workspace,listener);
-            if(remoteInfo.revision > localInfo.revision)
+            if(remoteInfo.revision > localInfo.revision) {
+                listener.getLogger().println(localInfo.url+" revision changed from "+localInfo.revision+" to "+remoteInfo.revision);
                 return true;    // change found
+            }
         }
 
         return false; // no change