Fix MessageTreeImplTest

briar-core/src/test/java/org/briarproject/briar/client/MessageTreeImplTest.java

@@ -83,11 +83,6 @@ public class MessageTreeImplTest {
 
 		}
 
-		@Override
-		public void setDescendantCount(int descendantCount) {
-
-		}
-
 		@Override
 		public long getTimestamp() {
 			return timestamp;