MB-100: added listing of view index directory into cbcollect_info

Change-Id: Iaffbe2877f6a6c3d2e57fe4e2133712425f19138
Reviewed-on: http://review.couchbase.org/25773
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>