ptserver: Avoid inet_ntoa

ptserver: Avoid inet_ntoa

The ptserver uses inet_ntoa in a few places, such as for calculating
host CPS. This isn't safe in pthreaded environments, so use
afs_inet_ntoa_r instead.

Reviewed-on: http://gerrit.openafs.org/8287
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit 527f2ba00c1247ae7e8d6f355572c8635331bc0c)

Change-Id: I3740a294bd93b000842ccd791f2a11cef5092a9a
Reviewed-on: http://gerrit.openafs.org/8546
Reviewed-by: Ken Dreyer <ktdreyer@ktdreyer.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Paul Smeddle <paul.smeddle@gmail.com>