Each datasource had a configurable field
update_method in the vitrage configuration file
where you can set it to update via:
none: don't update i.e. update only via the
periodic changes
pull: updates via polling the datasource every
configurable [changes_interval] seconds
push: updates via the datasource's push notifications
Change-Id: Iab884a357ae7235e137600c95b0a23052cdee064
Closes-Bug: #1606834
6bc84c97f3