added a test case for...

added a test case for http://www.nabble.com/unable-to-define-slave-in-%22use-for-tied-jobs-only%22-td21835058.html#a21835058

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@15164 71c3de6d-444a-0410-be80-ed276b4c234a

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

@@ -184,6 +184,10 @@ public abstract class Slave implements Node, Serializable {
         return mode;
     }
 
+    public void setMode(Mode mode) {
+        this.mode = mode;
+    }
+
     public RetentionStrategy getRetentionStrategy() {
         return retentionStrategy == null ? RetentionStrategy.Always.INSTANCE : retentionStrategy;
     }