Implementation of WL#2897: Complete definer support in the stored routines.

The idea is to add DEFINER-clause in CREATE PROCEDURE and CREATE FUNCTION
statements. Almost all support of definer in stored routines had been already
done before this patch.

NOTE: this patch changes behaviour of dumping stored routines in mysqldump.
Before this patch, mysqldump did not dump DEFINER-clause for stored routines
and this was documented behaviour. In order to get full information about stored
routines, one should have dumped mysql.proc table. This patch changes this
behaviour, so that DEFINER-clause is dumped.

Since DEFINER-clause is not supported in CREATE PROCEDURE | FUNCTION statements
before this patch, the clause is covered by additional version-specific comments.


client/mysqldump.c:
  Updated the code for dumping stored routines: cover DEFINER-clause
  into version-specific comment.
mysql-test/r/gis.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/information_schema.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/mysqldump.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/rpl_ddl.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/rpl_sp.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/rpl_trigger.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/sp-security.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/sp.result:
  Updated result file after adding DEFINER-clause.
mysql-test/r/sql_mode.result:
  Updated result file after adding DEFINER-clause.
mysql-test/t/sp-security.test:
  Updated result file after adding DEFINER-clause.
sql/sp.cc:
  Added DEFINER-clause.
sql/sp_head.cc:
  Added a new convenient variant of set_definer() operation.
sql/sp_head.h:
  Updated result file after adding DEFINER-clause.
sql/sql_lex.h:
  Renamed trigger_definition_begin into stmt_definition_begin to be used for
  triggers and stored routines.
sql/sql_parse.cc:
  Check DEFINER-clause.
sql/sql_trigger.cc:
  Renamed trigger_definition_begin into stmt_definition_begin to be used for
  triggers and stored routines.
sql/sql_yacc.yy:
  Added DEFINER-clause.

mysql-test/r/gis.result

@@ -680,7 +680,7 @@ drop procedure if exists fn3;
 create function fn3 () returns point return GeomFromText("point(1 1)");
 show create function fn3;
 Function	sql_mode	Create Function
-fn3		CREATE FUNCTION `fn3`() RETURNS point
+fn3		CREATE DEFINER=`root`@`localhost` FUNCTION `fn3`() RETURNS point
 return GeomFromText("point(1 1)")
 select astext(fn3());
 astext(fn3())