USE ELEMENTARY OS INSTALL UTILITY AND CLICK "INSTALL BOOT PICKER" TO INSTALL REFIND INSTEAD OF USING THIS. BETTER SUPPORT, FASTER BOOT, EDITABLE FROM OTHER OS'S, AUTO-UPDATES BOOT PICKER, AND MORE!
A rEFInd (UEFI boot picker) install utility for OS X
Allows the user to download the latest version and install it each with a single click of a button.
Download app from: https://goo.gl/LDLyEL
Click "Download" to download rEFInd from sourceforge, then click "Install" and enter your password if prompted. Done :)