Turn off cancel notifications
diff --git a/.travis.yml b/.travis.yml
index 370137f68d7..96c6fe414aa 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -105,6 +105,7 @@ notifications:
   irc:
     channels:
       - secure: "SGWZl3ownKx9xKVV2VnGt7DqkTmutJ89oJV9tjKhSs84kLijU6EYdPnllqISpfHMTxXflNZuxtGo0wTDYHXBuZL47w1O32W6nzuXdra5zC+i4sYQwYULUsyfOv9gJX8zWAULiK0Z3r0oho45U+FR5ZN6TPCidi8/eGU+EEPwaAw="
+    on_cancel: never
     on_success: never
     on_failure: always
     use_notice: true

By default, Travis cancels builds on branches and PRs if another commit lands in favor of running tests on that. See https://blog.travis-ci.com/2017-09-21-default-auto-cancellation.

I think this behavior is good as it stops us spending resources testing out of date code, but with our current setup, it causes Travis to send us notifications when builds are automatically canceled on master.

This PR changes that by not sending out notifications when a build gets canceled.