- A race condition caused brief unavailablility when trying to acccess
  a table.
- The unprotected variable 'grant_option' wasn't intended to alternate
  during normal execution. Variable initialization moved to grant_init
  a lines responsible for the alternation are removed. 


sql/mysqld.cc:
  - Added documentation to describe grant_option flag.
sql/sql_acl.cc:
  - This patch removes lines which causes grant_option to alternate and moves
    variable initialization to the grant_init()-function.