HDFS-16551. CryptoInputStream#close() should be syncronized (#4227)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java

@@ -311,7 +311,7 @@ public class CryptoInputStream extends FilterInputStream implements
   }
   
   @Override
-  public void close() throws IOException {
+  public synchronized void close() throws IOException {
     if (closed) {
       return;
     }