* gnu/services/ssh.scm (openssh-config-file): Add 'print-last-log?' option.
(<openssh-configuration>)[print-last-log?]: Add it.
(openssh-activation): Touch /var/log/lastlog.
* doc/guix.texi (Networking Services): Document 'print-last-log?'.
Before that, the service did not work as expected because /var/log/lastlog did
not exist.
Signed-off-by: Danny Milosavljevic <dannym@scratchpost.org>