Fix typo in --default-store-engine help. (Bug #11534)

sql/mysqld.cc:
  Fix typo

sql/mysqld.cc

@@ -4458,7 +4458,7 @@ Disable with --skip-bdb (will save memory).",
    (gptr*) &default_collation_name, (gptr*) &default_collation_name,
    0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0 },
   {"default-storage-engine", OPT_STORAGE_ENGINE,
-   "Set the default storage engine (table tyoe) for tables.", 0, 0,
+   "Set the default storage engine (table type) for tables.", 0, 0,
    0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
   {"default-table-type", OPT_STORAGE_ENGINE,
    "(deprecated) Use --default-storage-engine.", 0, 0,