qemu: Fix access to auto-generated socket paths

qemu: Fix access to auto-generated socket paths

We are automatically generating some socket paths for domains, but all
those paths end up in a directory that's the same for multiple domains.
The problem is that multiple domains can each run with different
seclabels (users, selinux contexts, etc.).  The idea here is to create a
per-domain directory labelled in a way that each domain can access its
own unix sockets.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1146886

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