User 'alt_demo' user instead of 'demo' for cli tests

In a bunch of cli tests we check how tenant isolation works, for
this we authorize as an admin user and as a alt user.
Prevously we used tempest config and took credentials from it,
in this config user alt_username was equal to 'alt_demo', that's why
there weren't any problems during all tests execution on every commit
to mistral repo, cause api tests run under 'demo' user, cli tests under -
admin and alt_demo. Now after removing usage of tempest config we use
'demo' user as an alt_user, that's why we have conflicts, when after
api tests action executions are left and we get them during cli tests.

Change-Id: I17d42a2d7a311fe44733878dddcb250770950e25

functionaltests/run_tests.sh

@@ -27,7 +27,7 @@ export MISTRALCLIENT_DIR="$BASE/new/python-mistralclient"
 
 # Get demo credentials.
 cd ${BASE}/new/devstack
-source openrc demo demo
+source openrc alt_demo alt_demo
 
 export OS_ALT_USERNAME=${OS_USERNAME}
 export OS_ALT_TENANT_NAME=${OS_TENANT_NAME}