Update the local copy of the image schema to reflect Image API 2.6.

Change-Id: Ib0e56027927880d0fa198ffd8ea4b57e39f9d0fe
Closes-bug: #1762044
Depends-on: https://review.openstack.org/#/c/560126/
(cherry picked from commit e89fcae346eee1e3e5b5beb65e641fbc666fd59c)

Add checks to image-import command so that it provides better user
feedback in failure situations.

Change-Id: I8b6b32c3d1d1a745aa68ff8dc629419dff9bb130
Closes-bug: #1758718
(cherry picked from commit 46dd4dd60fa31aff71f3ba94cf496aa6fea0d582)

Add checks to the image-create-via-import commmand so that it provides
better user feedback and doesn't begin the import workflow unless the
input has a chance of succeeding.  Preserves backward compatibility
with the current image-create command by (1) allowing an image record
only to be created when no import-method is specified AND no data is
supplied, and (2) doing the glance-direct workflow when no import-
method is specified AND data is provided.  Also adds the ability for
the import-method to be set as an env var OS_IMAGE_IMPORT_METHOD.

Change-Id: I0a225f5471a9311217b5d90ebb5fd415c369129a
Closes-bug: #1758149
(cherry picked from commit 79543a67edd7a15aa23426548d3be9ac5b99366d)

Fail image-create-via-import requests for the web-download import
method that don't include values for container_format or disk_format.

Closes-bug: #1757927

Depends-on: I0e1d18844f64723608288de473e97710798eb602

Change-Id: Ic5c81916823ff32f2dbddd32b40e825de0697dc9
(cherry picked from commit 6cd537e2748fa636aa3061812b257d549a6d603f)

This change adds support for 'web-download' import method
to 'image-import' and 'create-image-via-import' call.
To use this 'web-download' import method, user needs to pass
--uri option 'a valid uri to external image to import in glance'
to 'image-import' and 'create-image-via-imaport' calls.

Co-authored-by: Pranali Deore <pdeore@redhat.com>
Co-authored-by: Erno Kuvaja <jokke@usr.fi>

Closes-Bug: #1758039

Change-Id: I0e1d18844f64723608288de473e97710798eb602
(cherry picked from commit aedabec9e46e80266cdefb315f112a30927e216a)

Due to the 'glanceclient.common.utils.add_req_id_to_object' decorator,
an instance of 'glanceclient.common.utils.RequestIdProxy' is returned
for most calls in glanceclient. If we wish to compare to None, we have
to compare the contents of this wrapper and not the wrapper itself.

Unit tests are updated to highlight this.

Change-Id: I7dadf32d37ac2bda33a92c71d5882e9f23e38a82
Closes-Bug: #1736759

CLI image-create-via-import fails with ValueError. The reason
is create command returns RequestIdWrapper object and not image
and response.

Further it fails with AttributeError: 'Namespace' object has
no attribute 'import_method'. The reason is do_import_image() call
requires 'import_method' as input which is not provided at the
moment.

Change-Id: Ic4c4d1f3c5d290b584840e8f9047fb53611a5748
Closes-bug: #1711511