follow suit with the rax refactor and split out the slugify code

library/cloud/rax_facts

@@ -90,14 +90,16 @@ except ImportError:
 NON_CALLABLES = (basestring, bool, dict, int, list, NoneType)
 
 
+def rax_slugify(value):
+    return 'rax_%s' % (re.sub('[^\w-]', '_', value).lower().lstrip('_'))
+
+
 def pyrax_object_to_dict(obj):
     instance = {}
     for key in dir(obj):
         value = getattr(obj, key)
         if (isinstance(value, NON_CALLABLES) and not key.startswith('_')):
-            key = 'rax_' + (re.sub('[^A-Za-z0-9\-]', '_', key)
-                            .lower()
-                            .lstrip('_'))
+            key = rax_slugify(key)
             instance[key] = value
     return instance