gp: Fix NameError: free variable 'cron_dir' in Crontab CSE

gp: Fix NameError: free variable 'cron_dir' in Crontab CSE

An apply reports the error "NameError: free
variable 'cron_dir' referenced before assignment
in enclosing scope". This only happens when no
policy is defined for this CSE, because existing
policy causes the variable to be defined.

Moved the 'cron_dir' varilable to the correct
scope.

Signed-off-by: David Mulder <dmulder@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): David Mulder <dmulder@samba.org>
Autobuild-Date(master): Wed Apr 19 21:21:10 UTC 2023 on atb-devel-224