Open Stack

Hi, I'd like you to take a look at this patch for potential
DocImpact.
https://review.openstack.org/32379

Log:
commit 18b711f6ee8c32064123e727108655c4f1cbc5d0
Author: Alvaro Lopez Garcia <aloga at ifca.unican.es>
Date:   Fri Jun 7 11:01:16 2013 +0200

    New flag to handle the disk driver for libvirt and Xen.
    
    There are two versions of the blktap [1] driver available under Xen.
    blktap1 has been replaced by blktap2 that does not support "tap"
    devices but "tap2", therefore we should use "tap2" devices by default.
    
    This change adds support for this but also lets the user to select the
    old "blktap" driver if they are using still an old version, or even the
    "file" driver directly.
    
    Fixes bug 1188517
    Fixes bug 1084618
    DocImpact
    
    Change-Id: I8b46885b0909de7cb51fd2d0f6ba2e9bcbf33cc6