Bug#402994: use new libpaper hook to track system paper size

[Ralf Stubner <ralf.stubner@web.de>]

Ralf Stubner wrote:

> - actually neither 'a4' nor 'letter' as defined in config.ps should not
>   be used as default paper sizes; one should use A4size or letterSize; 
>   see the end of '4.2 Configuration file paper size command' in the dvips
>   documentation (texdoc dvips)
> 
> The latter point might actually be a bug in texconfig and/or the default
> config.ps. 

Actually this latter point is not quite correct (typically it is really
difficult to find errors in TE's scripts). When texconfig is called as

 texconfig paper letter


than 'letterSize' is used as default paper size for dvips (and 'us' for
xdvi). Only when one explicitly uses

 texconfig dvips paper letter

'letter' and not 'letterSize' is set as default. This is what I tested.
Similar for a4 vs. A4paper.

cheerio
ralf