Use the .. Perl operator to simplify prerms.

invirt-console-host, invirt-dev, and all of the packages in
xvm-munin-config previously used a convoluted one-liner to clean up
/etc/sudoers, but we can do it much more easily using the .. operator.

Taken from http://blog.ksplice.com/2010/05/top-10-perl-one-liner-tricks/

svn path=/trunk/packages/invirt-console/; revision=3011