VM: Use -serial none in no-graphics kvm mode...

...so that the console doesn't get messed up due to the serial port being
redirected from stdin.

BUG=8729
TEST=./bin/cros_run_parallel_vm_tests suite_Smoke suite_Smoke; checked console

Change-Id: I5a0cedba2b0ac7f453b4574666c645e84b30b379

Review URL: http://codereview.chromium.org/4501001

bin/cros_run_parallel_vm_tests.py

@@ -64,10 +64,6 @@ class ParallelTestRunner(object):
     """
     ssh_port = self._base_ssh_port
     spawned_tests = []
-    # Test runs shouldn't need anything from stdin. However, it seems that
-    # running with stdin leaves the terminal in a bad state so redirect from
-    # /dev/null.
-    dev_null = open('/dev/null')
     for test in self._tests:
       args = [ os.path.join(os.path.dirname(__file__), 'cros_run_vm_test'),
                '--snapshot',  # The image is shared so don't modify it.
@@ -84,8 +80,7 @@ class ParallelTestRunner(object):
       if self._order_output:
         output = tempfile.NamedTemporaryFile(prefix='parallel_vm_test_')
         Info('Piping output to %s.' % output.name)
-      proc = subprocess.Popen(args, stdin=dev_null, stdout=output,
-                              stderr=output)
+      proc = subprocess.Popen(args, stdout=output, stderr=output)
       test_info = { 'test': test,
                     'proc': proc,
                     'output': output }

lib/cros_vm_lib.sh

@@ -40,7 +40,7 @@ function start_kvm() {
     local nographics=""
     local usesnapshot=""
     if [ ${FLAGS_no_graphics} -eq ${FLAGS_TRUE} ]; then
-      nographics="-nographic"
+      nographics="-nographic -serial none"
     fi
 
     if [ ${FLAGS_snapshot} -eq ${FLAGS_TRUE} ]; then