virt-aa-helper: add unix channels (esp for qemu-guest-agent)

The original bug report was at
https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1393842

Also skip abstract unix sockets.
Signed-off-by: NSerge Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: NJán Tomko <jtomko@redhat.com>

src/security/virt-aa-helper.c

@@ -998,8 +998,10 @@ get_files(vahControl * ctl)
             (ctl->def->channels[i]->source.type == VIR_DOMAIN_CHR_TYPE_PTY ||
              ctl->def->channels[i]->source.type == VIR_DOMAIN_CHR_TYPE_DEV ||
              ctl->def->channels[i]->source.type == VIR_DOMAIN_CHR_TYPE_FILE ||
+             ctl->def->channels[i]->source.type == VIR_DOMAIN_CHR_TYPE_UNIX ||
              ctl->def->channels[i]->source.type == VIR_DOMAIN_CHR_TYPE_PIPE) &&
-            ctl->def->channels[i]->source.data.file.path)
+            ctl->def->channels[i]->source.data.file.path &&
+            ctl->def->channels[i]->source.data.file.path[0] != '\0')
             if (vah_add_file_chardev(&buf,
                                      ctl->def->channels[i]->source.data.file.path,
                                      "rw",