avoid compiler warning with DEBUGGING

[Christopher Faylor]

On Wed, May 20, 2009 at 06:51:19AM -0600, Eric Blake wrote:
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
>I noticed a complaint about comparing signed and unsigned values, when
>compiling with DEBUGGING enabled.  net.cc also has a lot of trailing blanks.
>
>2009-05-20  Eric Blake  <ebb9@byu.net>
>
>	* net.cc (gethostby_helper): Use correct signedness.

I've applied this even though I couldn't duplicate the problem with gcc 4.
I think that may be a first since gcc 4 is much more picky than gcc 3.4.

Thanks.

cgf