Due to the setup of the modular daemon service files the reverting to non-socket
activated daemons could have never worked.  The reason is that masking the
socket files prevents starting the daemons since they require (as in Requires=
rather than Wants= in the service file) the sockets.  On top of that it creates
issues with some libvirt-guests setups and needlessly increases our support
matrix.

Nothing prevents users to modify their setup in a way that will still work
without socket activation, but supporting such setup only creates burden on our
part.

This technically reverts most of commit 59d30ada

 except the change made to
the libvirtd manpage since the monolithic daemon still supports traditional mode
of starting even on systemd.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>