buffet: Read privet options from buffet.conf

Privet code is part of buffet, so it does not need separate config.

BUG=brillo:1213
TEST=`FEATURES=test emerge-gizmo buffet`

Change-Id: I8b2ecb4143aa5d50555fcdc45c3708992187db4d
Reviewed-on: https://chromium-review.googlesource.com/277706
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
diff --git a/buffet/privet/privet_manager.h b/buffet/privet/privet_manager.h
index 25ff43b..c54b6f0 100644
--- a/buffet/privet/privet_manager.h
+++ b/buffet/privet/privet_manager.h
@@ -54,6 +54,7 @@
     bool disable_security{false};
     bool enable_ping{false};
     std::set<std::string> device_whitelist;
+    base::FilePath config_path;
   };
 
   Manager();