Refactor factories

Change module factories from returning a blueprint.Module and a list
of property structs to returning an android.Module, which holds the
list of property structs.

Test: build.ninja identical except for Factory: comment lines
Change-Id: Ica1d823f009db812c518f271a386fbff39c9766f
diff --git a/python/python.go b/python/python.go
index ab80e4d..df5999d 100644
--- a/python/python.go
+++ b/python/python.go
@@ -152,14 +152,15 @@
 var _ android.AndroidMkDataProvider = (*pythonBaseModule)(nil)
 
 func InitPythonBaseModule(baseModule *pythonBaseModule, subModule PythonSubModule,
-	hod android.HostOrDeviceSupported,
-	props ...interface{}) (blueprint.Module, []interface{}) {
+	hod android.HostOrDeviceSupported) android.Module {
 
 	baseModule.subModule = subModule
 
-	props = append(props, &baseModule.properties)
+	baseModule.AddProperties(&baseModule.properties)
 
-	return android.InitAndroidArchModule(baseModule, hod, android.MultilibCommon, props...)
+	android.InitAndroidArchModule(baseModule, hod, android.MultilibCommon)
+
+	return baseModule
 }
 
 // the tag used to mark dependencies within "py_libs" attribute.