.travis.yml: fix invalid syntax by removing a comment.

Correction for 236cc7f commit.

Author: php-coder

.travis.yml

@@ -42,9 +42,6 @@ after_failure:
       echo "===== REPORT START =====";
       cat target/robotframework-reports/log.html | gzip -c | base64;
       echo "===== REPORT END =====";
-
-      # Travis CI may miss a part of the huge output if we'll exit immediately
-      # See: https://github.com/travis-ci/travis-ci/issues/6018
       sleep 5;
     fi