aq update machine internal error if a VM has a local disk

[jouvin]

I defined a virtual machine attached to a host (aq machine --vmhost...) with a local disk, without any problem. Later, I tried to update it to be attached to a cluster with the following command:

aq update machine --mach svomvm1 --cluster openstack_vd

but it resulted in the unexpected error:

Internal Server Error: 'LocalDisk' object has no attribute 'backing_store' 

Whether it is valid to have a local disk on a VM is discussable but the behaviour should be consistent between add and update and if it is an error, it should be properly handled rather than result in an internal error.

The machine attributes are:

Machine: svomvm1
  Primary Name: svom-base.lal.in2p3.fr [134.158.74.254]
  Hosted by: Host grid220.lal.in2p3.fr
  Building: bat206
  City: orsay
  Continent: europe
  Country: france
  Hub: upsaclay
  Organization: lal
  Rack: bat2061
    Row: 3
    Column: 1
    Fullname: rack03-01
  Room: salle-vd
  Vendor: virtual Model: os.1
    Model Type: virtual_machine
  Interface: eth0 00:50:56:01:20:00 [boot, default_route]
    Type: public
    Vendor: broadcom Model: bcm57711
    Network Environment: internal
    Provides: svom-base.lal.in2p3.fr [134.158.74.254]
  Cpu: virtual_cpu x 1
  Memory: 2048 MB
  Disk: sda 20 GB scsi (local) [boot]
  Host Personality: svom Archetype: virtual_servers
    Stage: current
    Environment: prod
    Owned by GRN: jouvin
    Host Feature: docker/lal [post_personality]
    Host Feature: emacs [post_personality]
    Host Feature: fail2ban [post_personality]
    Host Feature: java [post_personality]
    Host Feature: svom/base [post_personality]
    Host Feature: virtual_server [post_personality]
    Comments: SVOM hosts
  Host Archetype: virtual_servers [compilable]
    Required Service: dns
    Host Feature: timezone [post_personality]
    Host Feature: selinux/pdisk_home [post_personality]
    Host Feature: pakiti [post_personality]
  Operating System: centos
    Version: 7.x
    Lifecycle: evaluation
  Sandbox: jouvin/svom
  Build Status: build
  Advertise Status: False
  Owned by GRN: jouvin
  Host Feature: docker/lal [post_personality]
  Host Feature: emacs [post_personality]
  Host Feature: fail2ban [post_personality]
  Host Feature: java [post_personality]
  Host Feature: pakiti [post_personality]
  Host Feature: selinux/pdisk_home [post_personality]
  Host Feature: svom/base [post_personality]
  Host Feature: timezone [post_personality]
  Host Feature: virtual_server [post_personality]
  Uses Service: dns Instance: lal
  Host Comments: Base profile for SVOM images