[cbcollect_info] stop caring about membase

Because it's been more than 2 years ago. Even if some customer have
upgraded from 1.6, they cannot have anything from old installation
that still impacts supporting them.

Change-Id: I1082f54cb56f60e26e9823b9d31dee75047245e1
Reviewed-on: http://review.couchbase.org/38096
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>