From Justin's email:

I see some other problems in this broker upgrade section.

In step 3:

$ cp mkdir TEMPORARY_7.1_BROKER_INSTANCE_DIR

In step 7:

7. Start the upgraded 7.0.z broker by running the following command:

$ BROKER_INSTANCE_DIR/bin/artemis stop

How does that command start the 7.0.z broker, and wasn't I trying to upgrade to 7.1 anyhow?