Add application name to missing channel error

In sim, it is really hard to figure out where you messed up without a
debugger.  Application name provides a lot more hints about what went
wrong.

Change-Id: Ice762c13b2904b82725bd06d51adb0e3d42a2d28
diff --git a/aos/events/event_loop_tmpl.h b/aos/events/event_loop_tmpl.h
index 055e82c..06b1643 100644
--- a/aos/events/event_loop_tmpl.h
+++ b/aos/events/event_loop_tmpl.h
@@ -46,7 +46,8 @@
 
   CHECK(channel != nullptr)
       << ": Channel { \"name\": \"" << channel_name << "\", \"type\": \""
-      << MessageType::GetFullyQualifiedName() << "\" } not found in config.";
+      << MessageType::GetFullyQualifiedName()
+      << "\" } not found in config for application " << name() << ".";
 
   MakeRawWatcher(channel,
                  [this, w](const Context &context, const void *message) {
@@ -64,7 +65,8 @@
       name(), node());
   CHECK(channel != nullptr)
       << ": Channel { \"name\": \"" << channel_name << "\", \"type\": \""
-      << MessageType::GetFullyQualifiedName() << "\" } not found in config.";
+      << MessageType::GetFullyQualifiedName()
+      << "\" } not found in config for application " << name() << ".";
   MakeRawNoArgWatcher(channel, [this, w](const Context &context) {
     context_ = context;
     w();