Fix method signature for randomNextInt in test

Corrects syntax error in method override signature.

Author: dkropachev

core/src/test/java/com/datastax/oss/driver/internal/core/loadbalancing/DefaultLoadBalancingPolicyQueryPlanTest.java

@@ -475,7 +475,7 @@ protected long nanoTime() {
               }
 
               @Override
-              protected int randomNextInt(4) {
+              protected int randomNextInt(int bound) {
                 return diceRoll;
               }
             });