Add test for type none model dac seclabel

tests/qemuxml2argvdata/qemuxml2argv-seclabel-dac-none.args

+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \
+/usr/bin/qemu -name QEMUGuest1 -S -M pc -m 214 -smp 1 -nographic \
+-monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c \
+-usb -hda /dev/HostVG/QEMUGuest1 -net none -serial none -parallel none

tests/qemuxml2argvdata/qemuxml2argv-seclabel-dac-none.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static' cpuset='1-4,8-20,525'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <memballoon model='virtio'/>
+  </devices>
+  <seclabel type='none' model='dac'/>
+</domain>

tests/qemuxml2argvtest.c

@@ -1216,6 +1216,7 @@ mymain(void)
     DO_TEST("seclabel-static-relabel", QEMU_CAPS_NAME);
     DO_TEST("seclabel-static-labelskip", QEMU_CAPS_NAME);
     DO_TEST("seclabel-none", QEMU_CAPS_NAME);
+    DO_TEST("seclabel-dac-none", QEMU_CAPS_NAME);
 
     DO_TEST("pseries-basic",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_DEVICE, QEMU_CAPS_NODEFCONFIG);

tests/qemuxml2xmltest.c

@@ -304,6 +304,7 @@ mymain(void)
     DO_TEST("seclabel-static");
     DO_TEST_FULL("seclabel-static-labelskip", false, WHEN_ACTIVE);
     DO_TEST("seclabel-none");
+    DO_TEST("seclabel-dac-none");
     DO_TEST("numad-static-vcpu-no-numatune");
     DO_TEST("disk-scsi-lun-passthrough-sgio");