Update notifications settings for failing builds

Since travis send email by default only for PR, but send none by default for push checks

.travis.yml

@@ -19,3 +19,9 @@ jobs:
         - grunt --level=WHITESPACE_ONLY --base build --gruntfile build/Gruntfile.js
         - docker pull onlyofficetestingrobot/doc-builder-testing
         - docker run -v $PWD/word:/opt/onlyoffice/documentbuilder/sdkjs/word -v $PWD/cell:/opt/onlyoffice/documentbuilder/sdkjs/cell -v $PWD/slide:/opt/onlyoffice/documentbuilder/sdkjs/slide onlyofficetestingrobot/doc-builder-testing
+notifications:
+  email:
+    recipients:
+      - shockwavenn@gmail.com
+    on_success: never
+    on_failure: always