MB-100 Collect some information about transparent huge pages.

Change-Id: I02da02535a7f46d785a614191b647cab3e0be95c
Reviewed-on: http://review.couchbase.org/27663
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>