clocksi test: whitespace cleanups
clocksi test: add some more tests

1. Transactions with multiple keys
2. Multiple read and update on single key
Remove trigger downstream generation

This causes crash. Need to find out a better way to periodically update vectorclock.
clocksi: fix an error in clocksi and fix the test case which covers it

Record for keeping track of transactions in prepared phase was reading it wrongly. Hence DS could never see the pending transactions inroder to order operations.
clocksi: restructure read_fsm states so that it triggers downstream vnode only once