MB-100: cb-collect redhat_transparent_hugepage-s data too

For whatever reason rhel6.2 (and presumably later) has different
directory with info about this feature. So we gather it too.

Change-Id: If4b6a3cf9ad8a12e599e2514f4a0619b80f8ebce
Reviewed-on: http://review.couchbase.org/30221
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>