BF: fix goofy double "installing" message

matthew-brett · matthew-brett · commit de99a7603513 · 2016-05-23T12:17:02.000-04:00
Returning 'installing' from Windows check_requirements results in the
message '[installing, installing]', because the `check` method default
return string is also 'installing'.
diff --git a/setupext.py b/setupext.py
@@ -1883,7 +1883,7 @@ def check_requirements(self):
         config = self.get_config()
         if config is False:
             raise CheckFailed("skipping due to configuration")
-        return "installing"
+        return ""
 
     def get_extension(self):
         sources = [
