Handle gRPC connection error properly
Handle gRPC connection error properly

Fixed issue #159.

Huawei-PTLab/protoactor-go,Huawei-PTLab/protoactor-go,AsynkronIT/gam,AsynkronIT/protoactor-go,AsynkronIT/gam,rogeralsing/gam,AsynkronIT/protoactor-go