strict SQL mode

The problem was that a COMMENT longer than 64 characters
caused CREATE PROCEDURE to fail.

This patch fixed the problem by changing the COMMENT field in 
mysql.proc from char(64) to text. The corresponding ROUTINE_COMMENT
field in INFORMATION_SCHEMA.ROUTINES is also changed from
varchar(64) to longtext.

mysql_system_tables.sql and mysql_system_tables_fix.sql updated.
Test case added to sp.test and affected result-files updated.