Disable the v2.0 identity API by default

The v2.0 identity API is being removed in the Queens release, but in
order to do so we need to stop some v2.0 tempests tests from being
run. This commit switches the default to disable the keystone v2 api.
In a future commit after the removal of the api from keystone the bits
to deploy the v2 api will be removed.

Change-Id: I5afcba6321f496b8170be27789bee7c9ad8eacce

Author: mtreinish

stackrc

@@ -184,7 +184,7 @@ IDENTITY_API_VERSION=${IDENTITY_API_VERSION:-3}
 # will to be set to ``3`` in order to make DevStack register the Identity
 # endpoint as v3. This flag is experimental and will be used as basis to
 # identify the projects which still have issues to operate with Identity v3.
-ENABLE_IDENTITY_V2=$(trueorfalse True ENABLE_IDENTITY_V2)
+ENABLE_IDENTITY_V2=$(trueorfalse False ENABLE_IDENTITY_V2)
 if [ "$ENABLE_IDENTITY_V2" == "False" ]; then
     IDENTITY_API_VERSION=3
 fi