redis_server_protocol: remove Werror in thrift example

example/thrift_extension_c++/Makefile

@@ -21,7 +21,7 @@ include $(BRPC_PATH)/config.mk
 # Notes on the flags:
 # 1. Added -fno-omit-frame-pointer: perf/tcmalloc-profiler use frame pointers by default
 # 2. Added -D__const__= : Avoid over-optimizations of TLS variables by GCC>=4.8
-CXXFLAGS = $(CPPFLAGS) -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
+CXXFLAGS = $(CPPFLAGS) -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
 ifeq ($(NEED_GPERFTOOLS), 1)
 	CXXFLAGS+=-DBRPC_ENABLE_CPU_PROFILER
 endif

src/brpc/redis.h

@@ -128,7 +128,7 @@ public:
     void Print(std::ostream&) const;
 
 protected:
-    ::google::protobuf::Metadata GetMetadata() const;
+    ::google::protobuf::Metadata GetMetadata() const override;
 
 private:
     void SharedCtor();