Fix QEMU XML-2-ARGV graphics-spice-timeout test

The test used an emulator that is not supported in testutilsqemu.c.
Switch from qemu-kvm to kvm to fix this.

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

 LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=spice \
-/usr/bin/qemu-kvm -S -M pc-0.13 -cpu core2duo,+lahf_lm,+xtpr,+cx16,+tm2,\
+/usr/bin/kvm -S -M pc-0.13 -cpu core2duo,+lahf_lm,+xtpr,+cx16,+tm2,\
 +est,+vmx,+ds_cpl,+pbe,+tm,+ht,+ss,+acpi,+ds \
 -m 1024 -smp 2 -nodefaults -monitor unix:/tmp/test-monitor,server,nowait \
 -boot dc -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 \

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

@@ -38,7 +38,7 @@
   <on_reboot>restart</on_reboot>
   <on_crash>restart</on_crash>
   <devices>
-    <emulator>/usr/bin/qemu-kvm</emulator>
+    <emulator>/usr/bin/kvm</emulator>
     <disk type='file' device='disk'>
       <driver name='qemu' type='qcow2'/>
       <source file='/var/lib/libvirt/images/f14.img'/>