Dependency against libwww-perl if running against older distribution.

This is just a detail, but `HTTP::Daemon` is in package `libwww-perl`, not `libhttp-daemon-perl` in older versions of `libwww-perl` and `HTTP::Daemon` (there was a change between `libwww-perl` 5.x and 6.x).

This patch allows for the installation of this package on older (Squeeze) images. (It seems to work with `libwww-perl` 5.836.)