libweave: Extracted interaction with libwebserv into WebServClient

Class implements weave::HttpServer using libwebserv and it's going to be
moved out of libweave.

BUG=brillo:1252
TEST='FEATURES=test emerge-gizmo buffet'

Change-Id: I069831d50e39478c281073a62ad81ef63f3065a6
Reviewed-on: https://chromium-review.googlesource.com/290141
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Trybot-Ready: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
diff --git a/buffet/buffet.gyp b/buffet/buffet.gyp
index 1c619fa..c72b4d8 100644
--- a/buffet/buffet.gyp
+++ b/buffet/buffet.gyp
@@ -67,7 +67,7 @@
         '../libweave/src/privet/privet_types.cc',
         '../libweave/src/privet/publisher.cc',
         '../libweave/src/privet/security_manager.cc',
-        '../libweave/src/privet/privet_types.cc',
+        '../libweave/src/privet/webserv_client.cc',
         '../libweave/src/privet/wifi_bootstrap_manager.cc',
         '../libweave/src/privet/wifi_ssid_generator.cc',
         '../libweave/src/registration_status.cc',