addrConn: resetTransport loop cleanup (#2676)
addrConn: resetTransport loop cleanup (#2676)

Refactor retry loop after #2673


grpc/grpc-go,menghanl/grpc-go,dfawley/grpc-go,stanley-cheung/grpc-go,menghanl/grpc-go,dfawley/grpc-go,grpc/grpc-go,stanley-cheung/grpc-go