ci: Make sure notifications are always sent after successful and failed build

Change-Id: Idc7844361cf7b98dfd48d4319a06d4e0f7edc76a
diff --git a/.travis.yml b/.travis.yml
index 128be0b..e9fd66e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,10 @@
 language: cpp
 compiler:
   - gcc
+notifications:
+  email:
+    on_success: always
+    on_failure: always
 before_install:
   - travis_retry sudo add-apt-repository -y ppa:named-data/ppa
   - travis_retry sudo apt-get update -qq