Reopen the correct filename when -logfile is given

Reopen the correct filename when -logfile is given

The name of the log file passed to ReOpenLog() may not match the name
given in the initial OpenLog() call. This can happen when the -logfile
option is given to the fileserver or volume server.

Since the name given to ReOpenLog() must match the original name, change
ReOpenLog() to use the name previously given to OpenLog() and update all
callers.

Change-Id: Ie6fa4cb6e3c03f853efe0207bbec5d8412c6fe59
Reviewed-on: https://gerrit.openafs.org/11723
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>