Update playManifestAction.class.php

When serving a VOD, check if the StorageProfile belongs to the partner or is global (storageProfile->partner_id == 0)
Method retrieveExternalByPartnerId()

Method retrieveExternalByPartnerId() now seeks for both, the partnerId and the Global partner.
Merge pull request #1496 from visomar/IX-9.20.0-globalStorageProfiles

Added support to use Global storage profiles (partnerId = 0)