Address minor comments

src/core/ext/filters/client_channel/client_channel_channelz.h

@@ -37,7 +37,7 @@ class SubchannelNode : public BaseNode {
   SubchannelNode(const char* target_address, size_t channel_tracer_max_nodes);
   ~SubchannelNode() override;
 
-  // Used when the subchannel's transport connectivity state changes.
+  // Used when the subchannel's connectivity state changes.
   void UpdateConnectivityState(grpc_connectivity_state state);
 
   // Used when the subchannel's child socket uuid changes. This should be set

src/core/ext/filters/client_channel/subchannel.cc

@@ -679,7 +679,7 @@ Subchannel::Subchannel(SubchannelKey* key, grpc_connector* connector,
       (size_t)grpc_channel_arg_get_integer(arg, options);
   if (channelz_enabled) {
     channelz_node_ = MakeRefCounted<channelz::SubchannelNode>(
-        this->GetTargetAddress(), channel_tracer_max_memory);
+        GetTargetAddress(), channel_tracer_max_memory);
     channelz_node_->AddTraceEvent(
         channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("subchannel created"));