Add support for LUCI_CONTEXT.

recipe_modules/step/api.py

Index: recipe_modules/step/api.py
diff --git a/recipe_modules/step/api.py b/recipe_modules/step/api.py
index 789afd1df5e8e1ce80ea42ff433bd0adf258b017..199db48f78f6e59a86b1697d360fe817ae206e75 100644
--- a/recipe_modules/step/api.py
+++ b/recipe_modules/step/api.py
@@ -6,7 +6,6 @@
 etc.)."""
 
 import contextlib
-import copy
 import types
 
 from recipe_engine import recipe_api
@@ -210,6 +209,7 @@ class StepApi(recipe_api.RecipeApiPlain):
           prefixes=env_prefixes,
           pathsep=self.m.path.pathsep,
         ),
+        luci_context=self.m.context.luci_context,
         allow_subannotations=bool(allow_subannotations),
         trigger_specs=[self._make_trigger_spec(trig)
                        for trig in (trigger_specs or ())],