CBLT-252:  use: submodule update --init --recursive

Change-Id: I686f5846a1edcf1aa8f13947a302ce171ab6fc66
Reviewed-on: http://review.couchbase.org/35124
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>