Fix the check for a corrupt access log

Change-Id: I9ae7704a33f91a7a27858ff0170e467712468af3
Reviewed-on: http://review.couchbase.org/35508
Reviewed-by: Sundararaman Sridharan <sundar@couchbase.com>
Tested-by: Sundararaman Sridharan <sundar@couchbase.com>