virtio_console: Modify virtio_console to suit Windows testing

This patch changes the GuestWorker to run on windows and adjusts
virtio_console test also to support windows testing.

Currently supported tests are:
* open
* multiopen
* close
* max_serials_and_conosles (windows won't initialize consoles. I need
           to check it with the developer if this is a bug or feature)
* rw_host_offline (fails, need to check with developer the expected
                   results)
* basic_loopback (fails, data are corrupted)
* loopback (fails, data are corrupted)
* migrate (fails, data are corrupted)
* hotplug (fails, windows won't initialize consoles properly)
* shutdown

Beware on my laptop in 50% the ports were not initialized properly,
VM reboot usually helped (not always). You might use "Winobj" program
to list \\Device\vport* ports or \\.\$port_name devices/symlinks.

I checked the data corruption and it happends (winXP->Fedora18)
pretty regularly even with Amit's C++ testing script.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

kvm/tests/virtio_console.py

@@ -229,7 +229,8 @@ def run_virtio_console(test, params, env):
             if match != 1:  # Multiple open didn't fail:
                 raise error.TestFail("Unexpended pass of opening the"
                                      " serialport device for the 2nd time.")
-            elif not "[Errno 24]" in data:
+            elif ((not "[Errno 24]" in data) and
+                    (not "Access is denied" in data)):
                 raise error.TestFail("Multiple opening fail but with another"
                                      " exception %s" % data)
         port.open()
@@ -1010,6 +1011,9 @@ def run_virtio_console(test, params, env):
         @param cfg: virtio_console_params - which type of virtio port to test
         @param cfg: virtio_console_pause - pause between monitor commands
         """
+        # TODO: Support the new port name_prefix
+        # TODO: 101 of 100 ports are initialised (might be related to above^^)
+
         # TODO: Rewrite this test. It was left as it was before the virtio_port
         # conversion and looked too messy to repair it during conversion.
         # TODO: Split this test into multiple variants