Move Sauce credentials out of .travis.yml

Created by: cvrebert

And into the Travis settings page. CC: @XhmikosR

.travis.yml

@@ -25,10 +25,6 @@ cache:
 env:
   global:
     - NPM_CONFIG_PROGRESS="false"
-    - SAUCE_USERNAME="bootstrap"
-    - secure: "pJkBwnuae9dKU5tEcCqccfS1QQw7/meEcfz63fM7ba7QJNjoA6BaXj08L5Z3Vb5vBmVPwBawxo5Hp0jC0r/Z/O0hGnAmz/Cz09L+cy7dSAZ9x4hvZePSja/UAusaB5ogMoO8l2b773MzgQeSmrLbExr9BWLeqEfjC2hFgdgHLaQ="
-    - secure: "RKWpS+P20b4tG9tawzCMJSmQftoonmC7tJzyGYiHuEM1TcpHALLBcnzKlr/+DiPTfzDJWY4kS8pxfhK4uXOe8OHnhpMNub7LEWtFPePlZIervOJcsOydaQocTKqVVWD6OUubMeQmQ+tZmvmpjoJ1uPPEbFs9ciF7+dv3U5tLUZ0="
-    - secure: "XswSKBY0HJ/aO9VOBeWlvGpqSFF/DsJmNKz7o5RkJMJX340qe44J929uUNwwOwlv9YrgptzC2W6l8bpmZQV+p6IYs99SoSA8CCaUfIJaqeU9x/UiT5vIHgqaNax+vFJwvzHLpF5v/ggFqFEKCd54gCDasePLTztHeC4oL104iaQ="
   matrix:
     - TWBS_TEST=core
     - TWBS_TEST=validate-html