Ship the default image schema in the client

Now that we have stable branches for clients, it's easier to keep track
of the current default image's schema in Glance and update it
respectively. This patch adds the current image schema, including the
schema-properties.

One good reason to do this is to be able to react when a running Glance
instance is not around to be introspected. It's really unfortunate that
things like help text can't be rendered when there image schema is not
available in the system.

We could keep the schema in a json file but rather than shipping data
files with glanceclient we can just have it in the python modules.

Change-Id: I9b8cc1d18d6717ccf991fb8149ab13c06d653ee4
Closes-bug: #1481729

glanceclient/tests/unit/test_shell.py

@@ -158,6 +158,13 @@ class ShellTest(testutils.TestCase):
     def test_help_on_subcommand_error(self):
         self.assertRaises(exc.CommandError, shell, 'help bad')
 
+    def test_help_v2_no_schema(self):
+        shell = openstack_shell.OpenStackImagesShell()
+        argstr = '--os-image-api-version 2 help image-create'
+        actual = shell.main(argstr.split())
+        self.assertEqual(0, actual)
+        self.assertNotIn('<unavailable>', actual)
+
     def test_get_base_parser(self):
         test_shell = openstack_shell.OpenStackImagesShell()
         actual_parser = test_shell.get_base_parser()