Merge pull request #17131 from AspirinSJL/grpclb_fallback_fix

Update the RR policy even when fallback mode is disabled

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc

@@ -1333,11 +1333,8 @@ void GrpcLb::ProcessChannelArgsLocked(const grpc_channel_args& args) {
 
 void GrpcLb::UpdateLocked(const grpc_channel_args& args) {
   ProcessChannelArgsLocked(args);
-  // If fallback is configured and the RR policy already exists, update
+  // Update the existing RR policy.
-  // it with the new fallback addresses.
+  if (rr_policy_ != nullptr) CreateOrUpdateRoundRobinPolicyLocked();
-  if (lb_fallback_timeout_ms_ > 0 && rr_policy_ != nullptr) {
-    CreateOrUpdateRoundRobinPolicyLocked();
-  }
   // Start watching the LB channel connectivity for connection, if not
   // already doing so.
   if (!watching_lb_channel_) {