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.

Change-Id: I11521df50262ca80c7db21b7b44671d94bef3587
Reviewed-on: http://gerrit.openafs.org/11585
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: D Brashear <shadow@your-file-system.com>