Revert "Glasser code review comments"

This reverts commit a4a92b3f8f.

Going to squash and re-commit

packages/minimongo/call_in_observe_test.js

@@ -21,7 +21,7 @@ if (Meteor.isClient) {
       LocalCollection.find().observe({
         added: function () {
           Meteor.call("isRunningOnServer", function (err, res) {
-            test.isFalse(err);
+            test.equal(err, undefined);
             test.equal(res, true);
             done();
           });

packages/minimongo/minimongo.js

@@ -372,10 +372,6 @@ _.extend(LocalCollection.Cursor.prototype, {
         // be able to call `Meteor.call` within these wrapped
         // functions and actually end up calling a server method (as
         // opposed to just a client stub)
-        //
-        // XXX this shouldn't be necessary once #2315 is fixed (that
-        // is -- if we no longer run observe callbacks synchronously
-        // on Minimongo mutations).
         var wrapNotInMethodStub = function (f) {
           // It is strange that we refer to the `ddp` package directly
           // here. This pattern appears elsewhere in the code, but