Please fix an inconsistency on how the hostname is configured in d-i

[Walter Tautz <wtautz@cs.uwaterloo.ca>]

I just tried the March 31, i386 iso 120 Mb image and noticed that upon initial
boot that the hostname configuration portion of the network configuration allows
hostnames to have a dot in it -- perfectly OK, please leave it WHEREAS once the
system reboots and one goes hostname configuration of the Debian Base system
configuration dots are NOT allowed suddenly for the hostname.  My suggestion is
to correct this by ALLOWING dots. Clearly anyone who knows what they're doing
will realize that dots are allowed in hostname. Afterall the ndots option in
/etc/resolv.conf recognizes this possibility. Perhaps exim configuration can
also be told to recognize this possibility since it seems to think dots implies
domain names.... a separate issue I suppose.

I suppose this brings up the issue of why hostname configuration is done in two
different places which perhaps explains why it does it in an inconsistent way.
Presumably the solution is to have it done in one place AND to allow dots.