Fix segfault with -nographic, by Enache Adrian.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2538 c046a42c-6fe2-441c-8c8c-71466251a162

vl.c

@@ -7079,6 +7079,7 @@ int main(int argc, char **argv)
                 break;
             case QEMU_OPTION_nographic:
                 pstrcpy(serial_devices[0], sizeof(serial_devices[0]), "stdio");
+                pstrcpy(parallel_devices[0], sizeof(parallel_devices[0]), "null");
                 pstrcpy(monitor_device, sizeof(monitor_device), "stdio");
                 nographic = 1;
                 break;