Set different cloud name for alt_demu user

Having multiple clouds with the same name in clouds.yaml confuses
openstack client config and it may not choose the intended cloud.
Unfortunately the new alt_demo user's clouds.yaml config used a
duplicate name creating confusion for clouds.yaml consumers.

Correct this by using a unique cloud name, devstack-alt, for use by the
alt_demo user.

Change-Id: I2cb8f10ab5abfedf76ead309f237730ce8ce2ad4
diff --git a/functions-common b/functions-common
index 2a08f5f..b1f0a38 100644
--- a/functions-common
+++ b/functions-common
@@ -101,7 +101,7 @@
     # alt_demo -> devstack-alt
     $TOP_DIR/tools/update_clouds_yaml.py \
         --file $CLOUDS_YAML \
-        --os-cloud devstack \
+        --os-cloud devstack-alt \
         --os-region-name $REGION_NAME \
         --os-identity-api-version 3 \
         $CA_CERT_ARG \