Rename 2i index services listed in nodeServices API

Converted exposed 2i service names into camel case to
follow naming convention.

Change-Id: I65c663a53031eb359a1dd21cc2a7ad6df0233ab6
Reviewed-on: http://review.couchbase.org/44288
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>