Fix types in materialyzer and downstream operations
Fix get_primaries_preflist for partitions as hashkey
Merge branch 'origin/sequential_log'
clocksi: use partition id to find the preflist instead of key
clocksi: transactions wait until local vectorclock reaches vecsnapshottime
clocksi: sent vec_snapshot_time to downstreamop along with the updates
Find local dc_id by querying ring information.

dc_id is used to identify timestamps of each dc in vectorclock