added missing mock

Author: Joachim Hofer

rxjava-core/src/main/java/rx/operators/OperationInterval.java

@@ -32,6 +32,7 @@
 import rx.Subscription;
 import rx.concurrency.Schedulers;
 import rx.concurrency.TestScheduler;
+import rx.observables.ConnectableObservable;
 import rx.subscriptions.Subscriptions;
 import rx.util.functions.Action0;
 
@@ -98,6 +99,7 @@ public static class UnitTest {
         public void before() {
             scheduler = new TestScheduler();
             observer = mock(Observer.class);
+            observer2 = mock(Observer.class);
         }
 
         @Test