Rename concat test

Author: akarnokd

rxjava-core/src/test/java/rx/operators/OperationConcatTest.java renamed to rxjava-core/src/test/java/rx/operators/OperatorConcatTest.java

@@ -43,7 +43,7 @@
 import rx.subscriptions.BooleanSubscription;
 import rx.subscriptions.Subscriptions;
 
-public class OperationConcatTest {
+public class OperatorConcatTest {
 
     @Test
     public void testConcat() {