to the client connection, not to the error log.  This change will allow
innodb-index.test to be re-enabled.  It was previously disabled, because
mysql-test-run does not like output in the error log.

row_create_table_for_mysql(): Do not output anything to the error log
when reporting DB_DUPLICATE_KEY.  Let the caller report the error.
Add a TODO comment that the dict_table_t object is apparently not freed
when an error occurs.

create_table_def(): Convert InnoDB table names to the character set
of the client connection for reporting.  Use my_error(ER_WRONG_COLUMN_NAME)
for reporting reserved column names.  Report my_error(ER_TABLE_EXISTS_ERROR)
when row_create_table_for_mysql() returns DB_DUPLICATE_KEY.

rb://206