Sorry for making avtivity log  dirty.

I realized that the version of devstack I used is old . And after I updated to current  version , I also confirmed this bug is caused.

But ,  the reason of this problem is following commit of devstack .
--
Merge: 2d7c346 78b7726
Author: Jenkins <email address hidden>
Date:   Mon Jan 26 14:06:15 2015 +0000

    Merge "Configure auth_token middleware by auth plugin"

commit 905275ec9f51614911fbb915f8bba9896b3ab684
--

And ,  the commit merged by above log is following  ( <- sorry for poor English )

---
Author: Jamie Lennox <email address hidden>
Date:   Fri Dec 19 12:56:01 2014 +1000

    Configure auth_token middleware by auth plugin
    
    As of release 1.3 auth_token middleware can be configured to use any
    authentication plugin. This allows us to move to the more generic
    password mechanism which will default to using keystone v3 if available.
    
    This will allow in future revisions to move the devstack service users
    out of the default domain.
    
    Work will need to be done in heat to remove it's dependency on the
    (supposed to be private) keystone_authtoken CONF values.
    
    Change-Id: Ieac26806bd420aa08fc79bbc6a11eb6a1c15c7df

diff --git a/lib/keystone b/lib/keystone
index 1599fa5..9c15688 100644
--- a/lib/keystone
+++ b/lib/keystone
@@ -407,15 +407,6 @@ function create_keystone_accounts {
     fi
 }
 
-# Configure the API version for the OpenStack projects.
-# configure_API_version conf_file version [section]
-function configure_API_version {
-    local conf_file=$1
-    local api_version=$2
-    local section=${3:-keystone_authtoken}
-    iniset $conf_file $section auth_uri $KEYSTONE_SERVICE_PROTOCOL://$KEYSTONE_SERVICE_HOST:$KEYSTONE_SERVICE_PORT/v$api_version
-}
-
 # Configure the service to use the auth token middleware.
 #
 # configure_auth_token_middleware conf_file admin_user signing_dir [section]
@@ -429,15 +420,16 @@ function configure_auth_token_middleware {
     local signing_dir=$3
     local section=${4:-keystone_authtoken}
 
-    iniset $conf_file $section auth_host $KEYSTONE_AUTH_HOST
-    iniset $conf_file $section auth_port $KEYSTONE_AUTH_PORT
-    iniset $conf_file $section auth_protocol $KEYSTONE_AUTH_PROTOCOL
-    iniset $conf_file $section identity_uri $KEYSTONE_AUTH_URI
+    iniset $conf_file $section auth_plugin password
+    iniset $conf_file $section auth_url $KEYSTONE_AUTH_URI
+    iniset $conf_file $section username $admin_user
+    iniset $conf_file $section password $SERVICE_PASSWORD
+    iniset $conf_file $section user_domain_id default
+    iniset $conf_file $section project_name $SERVICE_TENANT_NAME
+    iniset $conf_file $section project_domain_id default
+
+    iniset $conf_file $section auth_uri $KEYSTONE_SERVICE_URI
     iniset $conf_file $section cafile $SSL_BUNDLE_FILE
-    configure_API_version $conf_file $IDENTITY_API_VERSION $section
-    iniset $conf_file $section admin_tenant_name $SERVICE_TENANT_NAME
-    iniset $conf_file $section admin_user $admin_user
-    iniset $conf_file $section admin_password $SERVICE_PASSWORD
     iniset $conf_file $section signing_dir $signing_dir
 }
 

commit 157c84b8766ae67f6868f26505ce9a5d7291730b
---

I don't understand why remove admin_user and insert username .
because as far as  I know other component also use admin_user yet.

So I think this bug is caused by devstack.