Since log_throttle is not available in 5.5. Logging of
error message for failure of thread to create new connection
in "create_thread_to_handle_connection" is not backported.

Since, function "my_plugin_log_message" is not available in 
5.5 version and since there is incompatibility between
sql_print_XXX function compiled with g++ and alog files with
gcc to use sql_print_error, changes related to audit log
plugin is not backported.