remove duplicate declare of ProcessWrite_SSL_Handshake()

Author: Tianyi Chen

src/include/network/connection_handle.h

@@ -166,11 +166,6 @@ class ConnectionHandle {
    */
   WriteState FlushWriteBuffer();
 
-  /**
-   * Flush out responses and process SSL handshake
-   */
-  Transition ProcessWrite_SSLHandshake();
-
   /**
    * @brief: process SSL handshake to generate valid SSL
    * connection context for further communications