[gnome-builder] waf: fix some warnings

[Christian Hergert <chergert src gnome org>]

commit 4e8d7da422c01db8c3c4572e731b286e70d11157
Author: Christian Hergert <chergert redhat com>
Date:   Fri Feb 22 22:43:28 2019 -0800

    waf: fix some warnings

 src/plugins/waf/waf_plugin.py | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/plugins/waf/waf_plugin.py b/src/plugins/waf/waf_plugin.py
index 31908582b..25fa29490 100644
--- a/src/plugins/waf/waf_plugin.py
+++ b/src/plugins/waf/waf_plugin.py
@@ -51,6 +51,8 @@ class WafBuildSystemDiscovery(Ide.SimpleBuildSystemDiscovery):
 
 class WafBuildSystem(Ide.Object, Ide.BuildSystem):
     project_file = GObject.Property(type=Gio.File)
+    python = None
+    waf_local = None
 
     def do_get_id(self):
         return 'waf'
@@ -67,6 +69,7 @@ class WafPipelineAddin(Ide.Object, Ide.PipelineAddin):
     stages and attaching them to phases of the build pipeline.
     """
     python = None
+    waf_local = None
 
     def do_load(self, pipeline):
         context = self.get_context()
@@ -87,6 +90,7 @@ class WafPipelineAddin(Ide.Object, Ide.PipelineAddin):
 
         # Avoid sniffing again later in targets provider
         build_system.python = self.python
+        build_system.waf_local = self.waf_local
 
         # Launcher for project configuration
         config_launcher = pipeline.create_launcher()