Add a pc-0.11 machine type and make the pc type an alias
The pc-0.11 type allows users of qemu-0.11 to use a machine type which
they know will remain compatible when the upgrade to qemu-0.12.
Management tools may choose to canonicalize the 'pc' machine type to
'pc-0.11' so that if the 'pc' alias changes target in future versions
of qemu, the machine type used will remain compatible.
Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>