Update .travis.yml and .kitchen.yml files

Change-Id: I691786f24ba962e9dac10d86dbf4a02286d4209a
diff --git a/.travis.yml b/.travis.yml
index a34a650..47b8712 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,6 +17,10 @@
     gem 'kitchen-salt', :git => 'https://github.com/salt-formulas/kitchen-salt.git'
   - bundle install
 
+env:
+  - PLATFORM=trevorj/salty-whales:trusty
+  - PLATFORM=trevorj/salty-whales:xenial
+
 before_script:
   - set -o pipefail
   - make test | tail