Bug #13667 Inconsistency for decimal(m,d) specification

Description:
See Bug#12694, which is about float/double.

I find a similar problem for decimal, but it depends on the
value of D.  For decimal(0,11), and error occurs, but for
D < 11, the column specification is accepted, and changed
silently without even a warning.

How to repeat:
Test script:

set sql_mode='';
drop table if exists t;
create table t (d decimal(0,11));
show warnings;
desc t;
drop table if exists t;
create table t (d decimal(0,10));
show warnings;
desc t;

Result:

mysql> set sql_mode='';
Query OK, 0 rows affected (0.00 sec)

mysql> drop table if exists t;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> create table t (d decimal(0,11));
ERROR 1427 (42000): For float(M,D), double(M,D) or decimal(M,D), M must be >= D (column 'd').
mysql> show warnings;
+-------+------+---------------------------------------------------------------------------+
| Level | Code | Message                                                                   |
+-------+------+---------------------------------------------------------------------------+
| Error | 1427 | For float(M,D), double(M,D) or decimal(M,D), M must be >= D (column 'd'). |
+-------+------+---------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> desc t;
ERROR 1146 (42S02): Table 'test.t' doesn't exist
mysql> drop table if exists t;
Query OK, 0 rows affected, 1 warning (0.01 sec)

mysql> create table t (d decimal(0,10));
Query OK, 0 rows affected (0.01 sec)

mysql> show warnings;
Empty set (0.01 sec)

mysql> desc t;
+-------+----------------+------+-----+---------+-------+
| Field | Type           | Null | Key | Default | Extra |
+-------+----------------+------+-----+---------+-------+
| d     | decimal(10,10) | YES  |     | NULL    |       |
+-------+----------------+------+-----+---------+-------+
1 row in set (0.02 sec)

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/30924

Ok to push.

Noted in 5.0.16 changelog.