Only install packages on ubuntu

CI is a *huge* pain.

Author: alanz

.travis.yml

@@ -19,9 +19,9 @@ before_install:
     if [ $TRAVIS_OS_NAME == "linux" ]; then
       export DISPLAY=':99.0'
       /usr/bin/Xvfb :99 -screen 0 1024x768x24 > /dev/null 2>&1 &
+      sudo apt-get update
+      sudo apt-get -y install  libsecret-1-dev
     fi
-  - sudo apt-get update
-  - sudo apt-get -y install  libsecret-1-dev
 install:
 - npm ci
 - npm run vscode:prepublish