Log expired items during warmup at INFO level

Change-Id: I564f61cb6affcf9d0f7d5ef9e36db1f9a4c7fed2
Reviewed-on: http://review.couchbase.org/38166
Reviewed-by: Sundararaman Sridharan <sundar@couchbase.com>
Tested-by: abhinav dangeti <abhinav@couchbase.com>