Specify the systemd unit dir so that the package can be created also
on systems where systemd is not installed during build time.
Recommend also dundee (part of oFono sources) and neard
Install systemd .service files using dh-systemd helper

Notice that Debian systemd < 208 has problems starting connman on bootup
using the supplied .service file.
Unofficial upstream packages were named as *-upstream
Rename unofficial upstream packages to *-upstream*.

The file split is different between the real Debian packages and the upstream
ones, thus name them differently.
Version number updated to 1.25