Reconnecting with vbUUID 0 results in a rollback

When a DCP stream is "End"ed with any of these reasons -

• ErrDCPStreamStateChanged
• ErrDCPStreamTooSlow
• ErrDCPStreamDisconnected
• ErrForcedReconnect (new in 7.0.2)

And, FTS reattempts the stream re-connection with possibly a non-zero start seqno and vbUUID as 0, KV returns a rollback response - causing FTS to unnecessary rollback and startover.

A change is warranted in this area - where FTS fetches the last available valid UUID for the vbucket from the failover log and use that to re-initiate the stream request.