let's be defensive here

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@7620 71c3de6d-444a-0410-be80-ed276b4c234a

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

@@ -78,6 +78,8 @@ public abstract class Actionable extends AbstractModelObject {
 
     public Object getDynamic(String token, StaplerRequest req, StaplerResponse rsp) {
         for (Action a : getActions()) {
+            if(a==null)
+                continue;   // be defensive
             String urlName = a.getUrlName();
             if(urlName==null)
                 continue;