avoid writing loopback addresses into CellServDB

avoid writing loopback addresses into CellServDB

Do not use loopback addresses for the server side CellServDB file.  Use
getaddrinfo() instead of gethostbyname() to look up a list of IPv4
addresses for a given hostname, and take the first non-loopback address.

This avoids writing a loopback address into the CellServDB on systems
such as Debian, which map the address 127.0.1.1 to the hostname in the
/etc/hosts file.

Reviewed-on: http://gerrit.openafs.org/11585
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: D Brashear <shadow@your-file-system.com>
(cherry picked from commit e4a8a7a38dbf29e89bc1a7b6b017447a6aa0c764)

Change-Id: Ib53b924b49c4c959c2228f953227e37fb94030a9
Reviewed-on: http://gerrit.openafs.org/12083
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>