Add pid to the stats for windows as well

Change-Id: I8b2c0ef6f06eaff3d92554724ee1944b6a13f97b
Reviewed-on: http://review.couchbase.org/33797
Reviewed-by: Dave Rigby <daver@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>