Update stack.sh to use openstackclient commands

There were a few instances of keystoneclient still being used,
these were replaced with their openstackclient equivalent.

Change-Id: I47fb7cf949b9ab054b97ae387ecbc6d7070fa9c3
diff --git a/stack.sh b/stack.sh
index e76a55c..b302e80 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1134,15 +1134,9 @@
 
 # Create an access key and secret key for nova ec2 register image
 if is_service_enabled key && is_service_enabled swift3 && is_service_enabled nova; then
-    NOVA_USER_ID=$(keystone user-list | grep ' nova ' | get_field 1)
-    die_if_not_set $LINENO NOVA_USER_ID "Failure retrieving NOVA_USER_ID for nova"
-    NOVA_TENANT_ID=$(keystone tenant-list | grep " $SERVICE_TENANT_NAME " | get_field 1)
-    die_if_not_set $LINENO NOVA_TENANT_ID "Failure retrieving NOVA_TENANT_ID for $SERVICE_TENANT_NAME"
-    CREDS=$(keystone ec2-credentials-create --user-id $NOVA_USER_ID --tenant-id $NOVA_TENANT_ID)
-    ACCESS_KEY=$(echo "$CREDS" | awk '/ access / { print $4 }')
-    SECRET_KEY=$(echo "$CREDS" | awk '/ secret / { print $4 }')
-    iniset $NOVA_CONF DEFAULT s3_access_key "$ACCESS_KEY"
-    iniset $NOVA_CONF DEFAULT s3_secret_key "$SECRET_KEY"
+    eval $(openstack ec2 credentials create --user nova --project $SERVICE_TENANT_NAME -f shell -c access -c secret)
+    iniset $NOVA_CONF DEFAULT s3_access_key "$access"
+    iniset $NOVA_CONF DEFAULT s3_secret_key "$secret"
     iniset $NOVA_CONF DEFAULT s3_affix_tenant "True"
 fi