logrotate: Bump version to 3.8.4

The changelog for logrotate indicates some CVE's were fixed in 3.8.0.
(changelog at http://svn.fedorahosted.org/svn/logrotate/tags/r3-8-4/CHANGES

)

Signed-off-by: Arne Rovet <arnerro@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>