The code which generates paths for UNIX socket blindly used target name
without checking if it was set. Thus for the following device XML
<channel type='unix'>
<source mode='bind'/>
<target type='virtio'/>
</channel>
we would generate "/var/lib/libvirt/qemu/channel/target/NAME.(null)"
path which works but is not really correct. Let's not use the
".target_name" suffix at all if target name is not set.
https://bugzilla.redhat.com/show_bug.cgi?id=1226854
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
