HADOOP-16372. Fix typo in DFSUtil getHttpPolicy method

Closes #967

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java

@@ -1476,7 +1476,7 @@ public class DFSUtil {
         DFSConfigKeys.DFS_HTTP_POLICY_DEFAULT);
     HttpConfig.Policy policy = HttpConfig.Policy.fromString(policyStr);
     if (policy == null) {
-      throw new HadoopIllegalArgumentException("Unregonized value '"
+      throw new HadoopIllegalArgumentException("Unrecognized value '"
           + policyStr + "' for " + DFSConfigKeys.DFS_HTTP_POLICY_KEY);
     }