cleanup: my_defaults, remove Process_option_func

This is a remnant of "MySQL Instance Manager", which was removed in
MySQL-5.5.0 and never existed in MariaDB

Remove callback, simplify and optimize the code accordingly.

include/my_default.h

@@ -26,10 +26,6 @@ extern const char *my_defaults_file;
 extern my_bool my_getopt_use_args_separator;
 extern my_bool my_getopt_is_args_separator(const char* arg);
 
-/* Define the type of function to be passed to process_default_option_files */
-typedef int (*Process_option_func)(void *ctx, const char *group_name,
-                                   const char *option);
-
 extern int get_defaults_options(int argc, char **argv,
                                 char **defaults, char **extra_defaults,
                                 char **group_suffix);
@@ -37,10 +33,6 @@ extern int my_load_defaults(const char *conf_file, const char **groups,
                             int *argc, char ***argv, const char ***);
 extern int load_defaults(const char *conf_file, const char **groups,
                          int *argc, char ***argv);
-extern int my_search_option_files(const char *conf_file, int *argc,
-                                  char ***argv, uint *args_used,
-                                  Process_option_func func, void *func_ctx,
-                                  const char **default_directories);
 extern void free_defaults(char **argv);
 extern void my_print_default_files(const char *conf_file);
 extern void print_defaults(const char *conf_file, const char **groups);