[PATCH 2/2] Update doc and test of 'set listsize'.

[Eli Zaretskii]

> From: Yao Qi <yao@codesourcery.com>
> Date: Sun, 9 Sep 2012 11:22:45 +0800
> 
> gdb/doc:
> 
> 2012-09-09  Yao Qi  <yao@codesourcery.com>
> 
> 	* gdb.texinfo (List): Describe the meaning of 0 and -1 in
> 	'set listsize'.

OK for this part.

Thanks.