fix for incorrect string split character in windows registry keys

Was receiving:

```
Comment: An exception occurred in this state: Traceback (most recent call last):
           File "c:\salt\salt-2014.1.4.win32\salt-2014.1.4-py2.7.egg\salt\state.py", line 1484, in call
             **cdata['kwargs'])
           File "c:\salt\salt-2014.1.4.win32\salt-2014.1.4-py2.7.egg\salt\states\reg.py", line 52, in present
             hive, path, key = _parse_key(name)
           File "c:\salt\salt-2014.1.4.win32\salt-2014.1.4-py2.7.egg\salt\states\reg.py", line 20, in _parse_key
             key = splt.pop(-1)
         IndexError: pop from empty list
```
Whenever using reg.present


Python interprets r'\\' as "\\\\", and we want to match on a single \ rather than a double, so we need to use "\\".