remove unused definition.

driver.c

@@ -187,8 +187,4 @@ void mrn_share_remove_all()
   /* TODO: implement this function by using GRN_HASH_EACH */
 }
 
-int mrn_create(mrn_table *share)
-{
-  return 0;
-}
 

driver.h

@@ -63,15 +63,12 @@ int mrn_deinit();
 void mrn_logger_func(int level, const char *time, const char *title,
 		     const char *msg, const char *location, void *func_arg);
 int mrn_flush_logs();
-grn_encoding mrn_charset_mysql_groonga(const char *csname);
-const char *mrn_charset_groonga_mysql(grn_encoding encoding);
 void mrn_ctx_init();
 grn_obj *mrn_db_open_or_create();
 mrn_table *mrn_share_get(const char *name);
 void mrn_share_put(mrn_table *share);
 void mrn_share_remove(mrn_table *share);
 
-
 /* static variables */
 extern grn_hash *mrn_hash_sys;
 extern grn_obj *mrn_db_sys, *mrn_lexicon_sys;