Fixed man-page creation with pod2man from >=perl-5.18

https://bugs.gentoo.org/490486

Signed-off-by: Lars Wendler <polynomial-c@gentoo.org>

--- rsnapshot-1.3.1/rsnapshot-program.pl
+++ rsnapshot-1.3.1/rsnapshot-program.pl
@@ -6716,6 +6716,8 @@
 
 =back
 
+=back
+
 =head1 USAGE
 
 B<rsnapshot> can be used by any user, but for system-wide backups