Rename a few global variables which hold hostname-related values to be

Rename a few global variables which hold hostname-related values to be
more sensible/understandable.  'from'->'from_host'  'host'->'local_host'
'fromb'->'frombuf'  'fromhost'->'origin_host'  and a local-variable
named 'host'->'hostbuf'.  This fixes some compile-time warnings about
local variables shadowing global variables.

Other than renaming variables, the only actual code changes are to call
strlcpy() instead of strncpy() when setting those (renamed) variables,
and that 'from_ip' is now a strdup()-created buffer instead of being a
static buffer compiled in as 1025 bytes.

Reviewed by:	freebsd-print@bostonradio.org (an earlier version)
MFC after:	1 week