Fixed typo in filename parameter. Fixes #74

Author: Pat Patterson

forcetk.js

@@ -311,7 +311,7 @@ if (forcetk.Client === undefined) {
                     } else if(request.status == 401 && !retry) {
                         that.refreshAccessToken(function(oauthResponse) {
                             that.setSessionToken(oauthResponse.access_token, null,oauthResponse.instance_url);
-                            that.blob(path, fields, fileName, file, callback, error, true);
+                            that.blob(path, fields, filename, file, callback, error, true);
                         },
                         error);
                     } else {