Eliminate _fetch on handles returned from cursor.observe()

This was originally introduced with
f1b77fec96, but it looks
like all of our tests now pass. (Maybe eliminating `rewind` in
b5a0613f85 made this no
longer necessary?)

If we find that this commit did break something, let's make sure to
add a failing test before reverting.

packages/minimongo/observe.js

@@ -177,32 +177,5 @@ LocalCollection._observeFromObserveChanges = function (cursor, observeCallbacks)
   var handle = cursor.observeChanges(changeObserver.applyChange);
   suppressed = false;
 
-  if (changeObserver.ordered) {
-    // Fetches the current list of documents, in order, as an array.  Can be
-    // called at any time.  Internal API assumed by the `observe-sequence`
-    // package (used by Meteor UI for `#each` blocks).  Only defined on ordered
-    // observes (those that listen on `addedAt` or similar).  Continues to work
-    // after `stop()` is called on the handle.
-    //
-    // Because we already materialize the full OrderedDict of all documents, it
-    // seems nice to provide access to the view rather than making the data
-    // consumer reconstitute it.  This gives the consumer a shot at doing
-    // something smart with the feed like proxying it, since firing callbacks
-    // like `changed` and `movedTo` basically requires omniscience (knowing old
-    // and new documents, old and new indices, and the correct value for
-    // `before`).
-    //
-    // NOTE: If called from an observe callback for a certain change, the result
-    // is *not* guaranteed to be a snapshot of the cursor up to that
-    // change. This is because the callbacks are invoked before updating docs.
-    handle._fetch = function () {
-      var docsArray = [];
-      changeObserver.docs.forEach(function (doc) {
-        docsArray.push(transform(EJSON.clone(doc)));
-      });
-      return docsArray;
-    };
-  }
-
   return handle;
 };

packages/observe-sequence/observe_sequence.js

@@ -86,7 +86,7 @@ ObserveSequence = {
         // more up-to-date information (specifically, the state of the observe
         // before it was stopped, which may be older than the DB).
         if (activeObserveHandle) {
-          lastSeqArray = _.map(activeObserveHandle._fetch(), function (doc) {
+          lastSeqArray = _.map(lastSeq.fetch(), function (doc) {
             return {_id: doc._id, item: doc};
           });
           activeObserveHandle.stop();