[FIXED HUDSON-6435] move "Checking cyclic dependencies" step to PLUGINS_PREPARED

to avoid possible ConcurrentModificationException when optional dependencies are
being processed in PLUGINS_LISTED phase.


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@31481 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/PluginManager.java

@@ -206,7 +206,7 @@ public abstract class PluginManager extends AbstractModelObject {
                                 });
                             }
 
-                            g.requires(PLUGINS_LISTED).add("Checking cyclic dependencies",new Executable() {
+                            g.requires(PLUGINS_PREPARED).add("Checking cyclic dependencies",new Executable() {
                                 /**
                                  * Makes sure there's no cycle in dependencies.
                                  */