added unset_zone_id context for clients
Cleanup metadata directory after test in StorageServiceTest
Initialize clientZoneId with unset_zone_id in ClientConfig
Use own node id during server startup + ZonedRebalanceNonContiguousZonesTest
Add tool (ZoneClipperCLI) to drop zone + shell script
Enable server side routing for tests that depend on it
Minor renaming and comment improvment
Add unit test for ZoneClipperCLI
Turning on server side routing for Slop auto purge test
Use symmetricDifference for set difference in test