util: fix log file renaming of mrafs-style logs

util: fix log file renaming of mrafs-style logs

Do not make timestamped log files with an invalid number of seconds when
renaming old mrsafs-style log files, i.e., more than 59 seconds in the
seconds field.

Replace the goto used in the mrafs-style make file name retries with a
regular, bounded loop.

Change-Id: I16d032197e4b1e227b1f005fbc395a013e099561
Reviewed-on: https://gerrit.openafs.org/12220
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>