fix checkstyle [NeedBraces]

Author: WangChengWei

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java

@@ -612,12 +612,13 @@ private int initMaxReplication(Configuration conf) throws IOException {
           + DFSConfigKeys.DFS_REPLICATION_MAX_KEY
           + " = " + maxR + " > " + Short.MAX_VALUE);
     }
-    if (minReplication > maxR)
+    if (minReplication > maxR) {
       throw new IOException("Unexpected configuration parameters: "
           + DFSConfigKeys.DFS_NAMENODE_REPLICATION_MIN_KEY
           + " = " + minReplication + " > "
           + DFSConfigKeys.DFS_REPLICATION_MAX_KEY
           + " = " + maxR);
+    }
     return maxR;
   }