Fix Debian bug #545940: Failure when run via ePN
If Perl's "shift" function is called outside of a subroutine and without
any argument, it usually shifts @ARGV. However, if a plugin is executed
via ePN, such a call will shift @_ instead, so we must explicitly
specify @ARGV for this to work as expected.
This fixes Debian bug #545940, see: http://bugs.debian.org/545940
Commit
de7191e3424e02ba278a39b86e8b1906a25d0362 fixed the same issue for
check_disk_smb.
(Reported by Hendrik Jaeger, forwarded by Jan Wagner.)