SHOW CREATE PROCEDURE and SHOW CREATE FUNCTION are fixed as well as
INFORMATION_SCHEMA.ROUTINES.ROUTINE_NAME.


mysql-test/r/information_schema.result:
  Add result for bug#20230.
mysql-test/t/information_schema.test:
  Add test case for bug#20230.
sql/sp_head.cc:
  Return NULL for routine definition if the user doesn't have enough
  privilege to see it.
sql/sql_show.cc:
  Make INFORMATION_SCHEMA.ROUTINES.ROUTINE_NAME NULL-able.  Return
  NULL if the user doesn't have enough privilege to see routine
  definition.