Deprecate glance APIs version config options

Glance v1 APIs are deprecated and v2 are current.
Tempest should tests only v2 APIs and by default v1
APIs are being disabled - I7f962a07317cdad917ee896d79e49ee18938d074

This commit deprecate the API version selection config options
so that we can switch to v2 only testing soon.

Change-Id: I6c4b92f0f2da2797efbb27e16061e6e325dda504
diff --git a/tempest/config.py b/tempest/config.py
index 274cd21..8795674 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -514,10 +514,20 @@
 ImageFeaturesGroup = [
     cfg.BoolOpt('api_v2',
                 default=True,
-                help="Is the v2 image API enabled"),
+                help="Is the v2 image API enabled",
+                deprecated_for_removal=True,
+                deprecated_reason='Glance v1 APIs are deprecated and v2 APIs '
+                                  'are current one. In future, Tempest will '
+                                  'test v2 APIs only so this config option '
+                                  'will be removed.'),
     cfg.BoolOpt('api_v1',
                 default=True,
-                help="Is the v1 image API enabled"),
+                help="Is the v1 image API enabled",
+                deprecated_for_removal=True,
+                deprecated_reason='Glance v1 APIs are deprecated and v2 APIs '
+                                  'are current one. In future, Tempest will '
+                                  'test v2 APIs only so this config option '
+                                  'will be removed.'),
     cfg.BoolOpt('deactivate_image',
                 default=False,
                 help="Is the deactivate-image feature enabled."