Fixing Python3 Octal Constant Compatibility Issue

Vim was displaying an syntax error in nrepl_fireplace.py when opening a clj file while running Python 3.3.3.  

According to http://docs.python.org/3.0/whatsnew/3.0.html, Octal constants of the form '037' were deprecated in Python 3.  The preferred form for both Python 2.6+ and Python 3 compatibility is to use '0o037'.