Wrap call to extension_supported on Launch Instance with try/except

[Lin Hua Cheng]

https://github.com/openstack/horizon/blob/master/openstack_dashboard/dashboards/project/instances/workflows/create_instance.py#L142

        if api.nova.extension_supported("BlockDeviceMappingV2Boot",
                                        request):
            source_type_choices.append(("volume_image_id",
                    _("Boot from image (creates a new volume).")))
        source_type_choices.append(("volume_snapshot_id",

extension_supported call can fail, we need to wrap this with try-except

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/62899

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/62899
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=2f85688ee629f84f36019391f460ff00c6b1501c
Submitter: Jenkins
Branch: master

commit 2f85688ee629f84f36019391f460ff00c6b1501c
Author: Lin Hua Cheng <email address hidden>
Date: Wed Dec 18 06:33:25 2013 -0800

    Wrap call to extension_supported with try/except

    Change-Id: I290b2cdc8dda116b48ccda73ec29e5f454febef0
    Closes-Bug: #1262223

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/59740
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=2c1f1f39565ca7bdc8a7bde2ce45f2a0019357da
Submitter: Jenkins
Branch: stable/havana

commit 2c1f1f39565ca7bdc8a7bde2ce45f2a0019357da
Author: Lin Hua Cheng <email address hidden>
Date: Thu Oct 17 13:02:23 2013 -0700

    Add check for BlockDeviceMappingV2 nova extension

    Booting instance from image (creates a volume) option is using
    the new BDM format when submitting the create server request to
    Nova. Adding a check for Nova extensions if it is supported
    before displaying the option.

    Closes-bug: #1223875

    In the original fix API call is not wrapped with try/except
    and it was fixed in bug 1262223 in master. The fix is also
    cherry-picked from commit a10436e6a376fb2c3478796e7ad728eb0e1f0ba3.

    Related-bug: #1262223

    Change-Id: Ie0b2b5d574babc910e2dac7ce9e3ab6603382ffb
    (cherry picked from commit a10436e6a376fb2c3478796e7ad728eb0e1f0ba3)