Re-enable GLOBAL_VENV

... because it is required to migrate the job to Noble. Note that
deployment of aodh-api will be switched to uwsgi by this change,
because mod_wsgi does not work with GLOBAL_VENV and uwsgi is now more
widely used in devstack deployment.

Change-Id: I8740c2abab6474b7786ea99d222e6f972e7f8095
diff --git a/.zuul.yaml b/.zuul.yaml
index 5d12ba6..6c73d69 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -38,7 +38,7 @@
         CEILOMETER_BACKENDS: "gnocchi,sg-core"
         CEILOMETER_PIPELINE_INTERVAL: 15
         CEILOMETER_ALARM_THRESHOLD: 6000000000
-        GLOBAL_VENV: False
+        AODH_DEPLOY: uwsgi
       devstack_local_conf:
         test-config:
           $TEMPEST_CONFIG: