CI failed at VM image building using diskimage-builder

[Itsuro Oda]

networking-spp CI job become failing with following error.
---
2020-06-05 06:27:51.684 | Cloning into 'diskimage-builder'...
2020-06-05 06:27:55.094 | warning: redirecting to https://opendev.org/openstack/diskimage-builder/
2020-06-05 06:27:57.346 | DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
2020-06-05 06:27:57.460 | Obtaining file:///opt/stack/networking-spp/devstack/image/dib/diskimage-builder
2020-06-05 06:27:58.747 | ERROR: Package 'diskimage-builder' requires a different Python: 2.7.17 not in '>=3.5'
2020-06-05 06:27:58.937 | /opt/stack/networking-spp/devstack/image/build_image.sh: line 55: disk-image-create: command not found
2020-06-05 06:27:59.232 | ++ /opt/stack/networking-spp/devstack/plugin.sh:prepare_tempest:309 : oscwrap --os-cloud=devstack-admin --os-region-name=RegionOne image create ubuntu-dpdk --public --container-format bare --disk-format qcow2
2020-06-05 06:27:59.232 | /opt/stack/networking-spp/devstack/plugin.sh: line 309: /opt/stack/networking-spp/devstack/image/image.qcow2: No such file or directory
2020-06-05 06:27:59.236 | + /opt/stack/networking-spp/devstack/plugin.sh:prepare_tempest:1 : exit_trap
---

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/734426

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/734426
Committed: https://git.openstack.org/cgit/x/networking-spp/commit/?id=6752e866153330f038bc8df13f5f58f01f139ca1
Submitter: Zuul
Branch: master

commit 6752e866153330f038bc8df13f5f58f01f139ca1
Author: Itsuro Oda <email address hidden>
Date: Tue Jun 9 15:18:37 2020 +0900

    Fix diskimage builder to python2.7

    Since VM building in networking-spp CI job is still dependent to
    python2.7, fix diskimage-builer to python2.7 supported version.

    It will be changed to use python3 in the future.

    Change-Id: I69dbd9e79b76bfc423fde45bffdd19e4c7f4e669
    Closes-Bug: #1882640

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/741576

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/741576
Committed: https://git.openstack.org/cgit/x/networking-spp/commit/?id=b085c58ccc3ff1050fac1009ba59c2141321659a
Submitter: Zuul
Branch: master

commit b085c58ccc3ff1050fac1009ba59c2141321659a
Author: Itsuro Oda <email address hidden>
Date: Mon Jul 6 07:45:10 2020 +0900

    Use python3 for diskimage builder

    This patch switches python2 to python3 to build the image used
    by tempest scenario test with diskimage-builder.

    This patch is the official fix of commit
    6752e866153330f038bc8df13f5f58f01f139ca1.

    Change-Id: I21404f0a3e80cc41976e7a93b3eb3925f21cc455
    Closes-Bug: #1882640