Fixed Zip issue with infinite streams.

Author: akarnokd

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

@@ -445,8 +445,9 @@ public void onNext(T value) {
                                     if (io.done) {
                                         observer.onCompleted();
                                         cancel.unsubscribe();
+                                        return;
                                     }
-                                    return;
+                                    continue;
                                 }
                                 Object v = io.queue.peek();
                                 if (v == NULL_SENTINEL) {
@@ -459,6 +460,8 @@ public void onNext(T value) {
                                     io.queue.poll();
                                 }
                                 observer.onNext(values);
+                            } else {
+                            	break;
                             }
                         }
                     } finally {