bot_update: Rewrite to use properties, and add override options for patches.

recipe_modules/bot_update/__init__.py

 DEPS = [
   'gclient',
   'recipe_engine/json',
   'recipe_engine/path',
   'recipe_engine/platform',
   'recipe_engine/properties',
   'recipe_engine/python',
   'recipe_engine/raw_io',
   'rietveld',
   'recipe_engine/step',
   'tryserver',
 ]
+
+from recipe_engine.recipe_api import Property
+
+PROPERTIES = {

[iannucci, 2016/03/01 22:36:22]

huge regret time: DEPS should probably have been in api.py... mer.

+  '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),
+  # TODO: convert to not using direct python argument, since this could probably
+  # cause unforseen bugs because of mutation
+  'deps_revision_overrides': Property(default={}),
+  'fail_patch': Property(default=False, kind=bool),
+}