Do not call get_non_local_subscription_count (#138)

Use the previous mechanism, and do not call that method but leave
it in the codebase.

Author: jfinken

rclcpp/include/rclcpp/publisher.hpp

@@ -273,7 +273,7 @@ class Publisher : public PublisherBase
     // It's not possible to do that with an unique_ptr,
     // as do_intra_process_publish takes the ownership of the message.
     bool inter_process_publish_needed =
-      get_non_local_subscription_count() > 0;
+        get_subscription_count() > get_intra_process_subscription_count();
 
     if (inter_process_publish_needed) {
       auto shared_msg =
@@ -351,7 +351,7 @@ class Publisher : public PublisherBase
     }
 
     bool inter_process_publish_needed =
-      get_non_local_subscription_count() > 0;
+        get_subscription_count() > get_intra_process_subscription_count();
 
     if (inter_process_publish_needed) {
       auto ros_msg_ptr = std::make_shared<ROSMessageType>();