Let tail attempt to open the file again, if it becomes inaccessible.
This is useful, when writing a reproducer that deletes pmbootstrap's
log.txt while at the same time running 'pmbootstrap log'.
(027724) [17:57:34] Done
tail: '/home/user/.local/var/pmbootstrap/log.txt' has become inaccessible: No such file or directory
tail: '/home/user/.local/var/pmbootstrap/log.txt' has appeared; following new file
(003493) [17:57:35] % cd /home/user/.local/var/pmbootstrap/cache_git/pmaports; git remote -v