fix typo

bubble-server/src/main/java/bubble/model/device/FlexRouter.java

@@ -110,6 +110,6 @@ public class FlexRouter extends IdentifiableBase implements HasAccount {
     // otherwise it would never sleep
     private boolean noInterrupt = false;
     public FlexRouter noInterrupt () { noInterrupt = true; return this; }
-    public boolean doInterrupt () { !noInterrupt; }
+    public boolean doInterrupt () { return !noInterrupt; }
 
 }