Fixed bug #11885.
sql_select.cc:
  Fixed bug #11885.
  Predicates of the forms 'a IN (v)' 'a NOT IN (v)' now
  is replaced by 'a=v' and 'a<>v' at the parsing stage.
sql_yacc.yy:
  Fixed bug #11885.
  Predicates of the forms 'a IN (v)' 'a NOT IN (v)' now 
  is replaced by 'a=v' and 'a<>v' at the parsing stage.