writeconfig: emit error messages again in VerifyEntries

writeconfig: emit error messages again in VerifyEntries

Before commit e4a8a7a38dbf29e89bc1a7b6b017447a6aa0c764 an error message
was printed if looking up a server hostname failed. Restore this, and
also print a message in the now detected case that the lookup returns
loopback addresses only.

Reviewed-on: http://gerrit.openafs.org/12097
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit f6247f90c9644d7a396531c219c585f705e0c251)

Change-Id: I6edc433cbbc8f2d8528501aa30b0aceafb85dbb6
Reviewed-on: http://gerrit.openafs.org/12105
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>