HBASE-26350 Add a DEBUG when we fail the SASL handshake

Closes #3743

Signed-off-by: Pankaj <pankajkumar@apache.org>
Signed-off-by: Tak Lon (Stephen) Wu <taklwu@apache.org>
Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org>

Author: joshelser

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/ServerRpcConnection.java

@@ -364,6 +364,7 @@ public void saslReadAndProcess(ByteBuff saslToken) throws IOException,
         replyToken = saslServer.evaluateResponse(saslToken.hasArray()?
             saslToken.array() : saslToken.toBytes());
       } catch (IOException e) {
+        RpcServer.LOG.debug("Failed to execute SASL handshake", e);
         IOException sendToClient = e;
         Throwable cause = e;
         while (cause != null) {