CBQE-0: fixes in increment upgrade test

Change-Id: I86ffe1c6be2167dbb2496b1b202a93b015fff975
Reviewed-on: http://review.couchbase.org/31478
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>