Don't warn on empty modules when scanning API

docs/sphinxext/apigen.py

@@ -220,7 +220,7 b' class ApiDocWriter(object):'
         # get the names of all classes and functions
         functions, classes = self._parse_module(uri)
         if not len(functions) and not len(classes):
-            print ('WARNING: Empty -', uri)  # dbg
+            #print ('WARNING: Empty -', uri)  # dbg
             return ''
 
         # Make a shorter version of the uri that omits the package name for