fixed a compilation problem.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@22996 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/Queue.java

@@ -33,6 +33,7 @@ import hudson.cli.declarative.CLIResolver;
 import hudson.remoting.AsyncFutureImpl;
 import hudson.model.Node.Mode;
 import hudson.model.queue.CauseOfBlockage;
+import hudson.model.queue.FoldableAction;
 import hudson.model.queue.CauseOfBlockage.BecauseLabelIsBusy;
 import hudson.model.queue.CauseOfBlockage.BecauseNodeIsOffline;
 import hudson.model.queue.CauseOfBlockage.BecauseLabelIsOffline;