Remove unnecessary include. (#264)

g-easy · web-flow · commit 5596caf065ac · 2018-12-19T16:42:50.000+11:00
diff --git a/opencensus/common/internal/grpc/with_user_agent.cc b/opencensus/common/internal/grpc/with_user_agent.cc
@@ -14,8 +14,6 @@
 
 #include "opencensus/common/internal/grpc/with_user_agent.h"
 
-#include <string>
-
 #include <grpcpp/support/channel_arguments.h>
 #include "opencensus/common/version.h"
 
