Bug #42714  	AUTO_INCREMENT errors in 5.1.31

Detailed revision comments:

r4287 | sunny | 2009-02-25 05:32:01 +0200 (Wed, 25 Feb 2009) | 10 lines
branches/5.1: Fix Bug#42714 AUTO_INCREMENT errors in 5.1.31. There are two
changes to the autoinc handling.

1. To fix the immediate problem from the bug report, we must ensure that the
   value written to the table is always less than the max value stored in
   dict_table_t.

2. The second related change is that according to MySQL documentation when
   the offset is greater than the increment, we should ignore the offset.