WL#15524 Patch #2 TLS-safe upgrade of mgm socket to transporter

Post push fix.

NdbSocket::copy method duplicated the mutex pointer, leaving two objects
referring to one mutex. Typically the source will destroy its mutex,
making it unusable for target object.

Remove copy method.

Change-Id: I2cc36128c343c7bab08d96651b12946ecd87210c

storage/ndb/include/util/NdbSocket.h

@@ -47,13 +47,9 @@ class NdbSocket {
   * NdbSockets should be copied using NdbSocket::transfer(), which
   * invalidates the original, and transfers ownership of its ssl and
   * mutex.
-  *
-  * NdbSocket::copy() should only be used when the original is going
-  * out of scope.
   */
   static void transfer(NdbSocket & newSocket, NdbSocket & original);
   static NdbSocket transfer(NdbSocket & original);
-  static NdbSocket copy(const NdbSocket &s) { return s; }
 
   void init_from_new(ndb_socket_t);
   void init_from_native(socket_t fd) { ndb_socket_init_from_native(s, fd); }