MB-8582: Specify indexer in couch_set_view:start_link/2

Change the signature of couch_set_view:start_link/1 to /2 in
order to include the indexer. This way the start_link function
can also be used for the spatial indexer.

Change-Id: I5e71134b1f55660560a9a7b21ae31443898dad83
Reviewed-on: http://review.couchbase.org/27612
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>