There was an improper order of doing chained operations.

To the documentor: ENABLE|DISABLE KEYS combined with RENAME TO, and no other
ALTER TABLE clause, leads to server crash independent of the presence of
indices and data in the table.


mysql-test/r/alter_table.result:
  update result
mysql-test/t/alter_table.test:
  add test for bug#24129
sql/sql_table.cc:
  If there is operation on the KEYS, first do it
  and then do a rename if there is such. Or, we will crash because
  the underlying table has changed.