Convert the bot_update module to use properties

recipe_modules/bot_update/__init__.py

Index: recipe_modules/bot_update/__init__.py
diff --git a/recipe_modules/bot_update/__init__.py b/recipe_modules/bot_update/__init__.py
index 928f7ea0b5e0e05ff16e11502502031fdedf1d27..dde0d69145e425fc13adde89e8a880cb24d06db5 100644
--- a/recipe_modules/bot_update/__init__.py
+++ b/recipe_modules/bot_update/__init__.py
@@ -10,3 +10,22 @@ DEPS = [
   'recipe_engine/step',
   'tryserver',
 ]
+
+from recipe_engine.recipe_api import Property
+from recipe_engine.types import freeze
+
+PROPERTIES = {
+  'mastername': Property(default=None),
+  'buildername': Property(default=None),
+  'slavename': Property(default=None),
+  'issue': Property(default=None),
+  'patchset': Property(default=None),
+  'patch_url': Property(default=None),
+  'repository': Property(default=None),
+  'event.patchSet.ref': Property(default=None, param_name="gerrit_ref"),
+  'rietveld': Property(default=None),
+  'revision': Property(default=None),
+  'parent_got_revision': Property(default=None),
+  'deps_revision_overrides': Property(default=freeze({})),
+  'fail_patch': Property(default=None, kind=str),
+}