qemuxml2argvtest: Pass some additional flags to graphics-spice-agentmouse

One of the recent commits introduced support for
spice agent-mouse. However, test for this feature
require some tweaking: pass QEMU_CAPS_CHARDEV_SPICEVMC |
QEMU_CAPS_NODEFCONFIG and add "-vga cirrus".

tests/qemuxml2argvdata/qemuxml2argv-graphics-spice-agentmouse.args

@@ -5,4 +5,4 @@ LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=spice \
 -hda /dev/HostVG/QEMUGuest1 -chardev spicevmc,id=charchannel0,name=vdagent \
 -device virtserialport,bus=virtio-serial1.0,nr=3,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 \
 -usb -spice port=5903,tls-port=5904,addr=127.0.0.1,agent-mouse=off,x509-dir=/etc/pki/libvirt-spice,tls-channel=main \
--device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
+-vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3

tests/qemuxml2argvdata/qemuxml2argv-graphics-spice-agentmouse.xml

@@ -31,6 +31,9 @@
       <target type='virtio' name='com.redhat.spice.0'/>
       <address type='virtio-serial' controller='1' bus='0' port='3'/>
     </channel>
+    <video>
+      <model type='cirrus' vram='9216' heads='1'/>
+    </video>
     <memballoon model='virtio'/>
   </devices>
 </domain>

tests/qemuxml2argvtest.c

@@ -513,7 +513,9 @@ mymain(void)
             QEMU_CAPS_DEVICE, QEMU_CAPS_SPICE);
     DO_TEST("graphics-spice-agentmouse", false,
             QEMU_CAPS_VGA, QEMU_CAPS_VGA_QXL,
-            QEMU_CAPS_DEVICE, QEMU_CAPS_SPICE);
+            QEMU_CAPS_DEVICE, QEMU_CAPS_SPICE,
+            QEMU_CAPS_CHARDEV_SPICEVMC,
+            QEMU_CAPS_NODEFCONFIG);
     DO_TEST("graphics-spice-compression", false,
             QEMU_CAPS_VGA, QEMU_CAPS_VGA_QXL,
             QEMU_CAPS_DEVICE, QEMU_CAPS_SPICE);