Make all the rest of the recipes explicitly specify GIT_MODE

scripts/slave/recipe_modules/skia/api.py

Index: scripts/slave/recipe_modules/skia/api.py
diff --git a/scripts/slave/recipe_modules/skia/api.py b/scripts/slave/recipe_modules/skia/api.py
index fb0f1a2f0198de76136974f94ab1b262fd4f418f..497aac1a7206edfda8df54bd0f793bc6d06d4ba7 100644
--- a/scripts/slave/recipe_modules/skia/api.py
+++ b/scripts/slave/recipe_modules/skia/api.py
@@ -295,7 +295,8 @@ class SkiaApi(recipe_api.RecipeApi):
 
   def checkout_steps(self):
     """Run the steps to obtain a checkout of Skia."""
-    cfg_kwargs = {'GIT_MODE': True}
+    cfg_kwargs = {}
+    cfg_kwargs['GIT_MODE'] = True
     if not self.persistent_checkout:
       # We should've obtained the Skia checkout through isolates, so we don't
       # need to perform the checkout ourselves.