Fix _find_file parent stop condition

see HBNetwork#172

Author: jdranczewski

decouple.py

@@ -219,7 +219,7 @@ def _find_file(self, path):
 
         # search the parent
         parent = os.path.dirname(path)
-        if parent and os.path.normcase(parent) != os.path.normcase(os.path.abspath(os.sep)):
+        if parent and os.path.normcase(parent) != os.path.normcase(path):
             return self._find_file(parent)
 
         # reached root without finding any files.