BUG 2339 : TransactionChain id created by the Clustered Data Store are not unique

The fix is to use a simple atomically incrementing integer to form the transaction chain
identifier instead of using the system time.

I also added a few log statements in there which were helpful in debugging the issue.

Change-Id: Ie1465f1640d6be0ff9da0f66477ebafc7ebff137
Signed-off-by: Moiz Raja <moraja@cisco.com>