MB-100: remove incr. index phase from general workload

Change-Id: I60f8176ef14365eafa1c4912437c4e10e1be3d36
Reviewed-on: http://review.couchbase.org/25560
Tested-by: Pavel Paulau <pavel.paulau@gmail.com>
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>