Avoid dict comprehension for compatibility.

This fixes #128.

rq/scripts/__init__.py

@@ -16,7 +16,9 @@ def add_standard_arguments(parser):
 def read_config_file(module):
     """Reads all UPPERCASE variables defined in the given module file."""
     settings = __import__(module, [], [], [], -1)
-    return {k: v for k, v in settings.__dict__.items() if k.upper() == k}
+    return dict([(k, v)
+            for k, v in settings.__dict__.items()
+            if k.upper() == k])
 
 
 def setup_default_arguments(args, settings):