Support patch number == 0 in sudo version string

Sudo has two kind of releases: patch 0 release, e.g, 1.8.5,
and the patch releases, e.g, 1.8.5p{6,7}. The patch 0 may
be considered as 1.8.5.0 and by the new support we will only
use 1 version scheme for sudo in our build system: x.y.z.t
The first/experimentatal implementation of :notify_system

We will add a new function to PKGBUILD that helps us to check the latest
information from the homepage. This will help package maintainers much.
See also
http://article.gmane.org/gmane.linux.distributions.theslinux.devel/56