RMap.replace race-condition fixed

src/main/java/org/redisson/RedissonMap.java

@@ -285,8 +285,8 @@ public class RedissonMap<K, V> extends RedissonExpirable implements RMap<K, V> {
                         }
                     } else {
                         connection.unwatch();
+                        return null;
                     }
-                    return null;
                 }
             }
         });

src/test/java/org/redisson/RedissonConcurrentMapTest.java

@@ -84,7 +84,7 @@ public class RedissonConcurrentMapTest extends BaseConcurrentTest {
             @Override
             public void run(Redisson redisson) {
                 ConcurrentMap<Integer, Integer> map = redisson.getMap(name);
-                map.replace(secureRandom.nextInt(5), 2);
+                Assert.assertNotNull(map.replace(secureRandom.nextInt(5), 2));
             }
         });