Description of problem:
When an IDE disk is added as a second disk by Add Hardware, and set as Readonly, the vm machine can not be started. Whenever the first disk is IDE or Virtio disk, this problem always occur.  

Version-Release number of selected component (if applicable):
virt-manager: virt-manager-0.8.6-3.el6
kernel: kernel-2.6.32-120.el6.x86_64
qemu-kvm: qemu-kvm-0.12.1.2-2.150.el6.x86_64
libvirt: libvirt-0.8.7-11.el6.x86_64

How reproducible:
Always

Steps to Reproduce:
1.Shut down a vm then open Virtual Machine Details window.
2.Click Hardware tab then Click Add Hardware, select Storage, Browse the test.img location and IDE Disk item.
3.Check this added IDE disk as Readonly.
4.Click "Apply" button.
5.Run the virtual machine.
  
Actual results:
Get the error message 

Expected results:
vm start successfully

Additional info:

-------------
Error Message
-------------
Error starting domain: internal error Process exited while reading console log output: char device redirected to /dev/pts/1
Using CPU model "cpu64-rhel6"
Using CPU model "cpu64-rhel6"
Using CPU model "cpu64-rhel6"
qemu-kvm: -device ide-drive,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1: Can't use a read-only drive
qemu-kvm: -device ide-drive,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1: Device 'ide-drive' could not be initialized

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 45, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/engine.py", line 956, in asyncfunc
    vm.startup()
  File "/usr/share/virt-manager/virtManager/domain.py", line 1048, in startup
    self._backend.create()
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 330, in create
    if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
libvirtError: internal error Process exited while reading console log output: char device redirected to /dev/pts/1
Using CPU model "cpu64-rhel6"
Using CPU model "cpu64-rhel6"
Using CPU model "cpu64-rhel6"
qemu-kvm: -device ide-drive,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1: Can't use a read-only drive
qemu-kvm: -device ide-drive,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1: Device 'ide-drive' could not be initialized

------------
dumpxml info
------------
<emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='none'/>
      <source file='/var/lib/libvirt/images/rhel6_x86_64_IDE.img'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' unit='0'/>
    </disk>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test.img'/>
      <target dev='hdb' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='0' unit='1'/>
    </disk>