libweave: Update comment on handling new commands

The old comment in DeviceRegistrationInfo::OnCommandCreated() was left
over from when the code would use the command received via the
notification channel. Now the code always fetches commands from the
command queue when it receives a notification that there is a new
command. The code ignores the actual command in the notification
payload.

Change-Id: I1b7f7eedc337280035a5a6ec45f5935f780cac7f
Reviewed-on: https://weave-review.googlesource.com/3190
Reviewed-by: John Mccullough <jmccullough@google.com>

src/device_registration_info.cc

diff --git a/src/device_registration_info.cc b/src/device_registration_info.cc
index b7ff589..6353e12 100644
--- a/src/device_registration_info.cc
+++ b/src/device_registration_info.cc
@@ -1330,9 +1330,7 @@
 
   VLOG(1) << "Command notification received: " << command;
 
-  // If the command was too big to be delivered over a notification channel,
-  // or OnCommandCreated() was initiated from the Pull notification,
-  // perform a manual command fetch from the server here.
+  // Manually fetch the command queue whenever a new command is received.
   FetchAndPublishCommands(fetch_reason::kNewCommand);
 }