5.6.7-rc fill_alter_inplace_info erroneous sets the ALTER_COLUMN_TYPE flag

[Rich Prohaska]

Suppose we have a table t (a char(1), b binary(1)).

If we run "alter table t change a aa char(1)", the ALTER_COLUMN_NAME
flag is set in the handler_flags.

If we run "alter table t change b bb binary(1), the ALTER_COLUMN_NAME
and ALTER_COLUMN_TYPE flags are set in the handler flags, even when
the type is unchanged.

I added code to our storage engine to really check the field types if
the ALTER_COLUMN_TYPE flag is set.