Merge pull request #14 from flatcar-linux/vbatts/protobuf

update_engine: remove undefined reference

Author: krnowak

src/update_engine/libcurl_http_fetcher.cc

@@ -14,7 +14,6 @@
 #include "update_engine/dbus_interface.h"
 #include "update_engine/utils.h"
 
-using google::protobuf::NewCallback;
 using std::max;
 using std::make_pair;
 using std::string;