Update kitchen image version, change linux locales for tests

Change-Id: I5b146c466d9ee4110fd54e0421e944524641e9f6
diff --git a/.travis.yml b/.travis.yml
index 0b24242..4ba771d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,19 +22,14 @@
   - bundle install
 
 env:
-  - PLATFORM=trevorj/salty-whales:trusty-2017.7 SUITE=network
-  - PLATFORM=trevorj/salty-whales:xenial-2017.7 SUITE=network
-  # - PLATFORM=trevorj/salty-whales:trusty-2017.7 SUITE=storage
-  # - PLATFORM=trevorj/salty-whales:xenial-2017.7 SUITE=storage
-  - PLATFORM=trevorj/salty-whales:trusty-2017.7 SUITE=system
-  - PLATFORM=trevorj/salty-whales:xenial-2017.7 SUITE=system
-  - PLATFORM=trevorj/salty-whales:trusty SUITE=network
-  - PLATFORM=trevorj/salty-whales:xenial SUITE=network
-  # - PLATFORM=trevorj/salty-whales:trusty SUITE=storage
-  # - PLATFORM=trevorj/salty-whales:xenial SUITE=storage
-  - PLATFORM=trevorj/salty-whales:trusty SUITE=system
-  - PLATFORM=trevorj/salty-whales:xenial SUITE=system
-## Test on both Salt version until there is new test policy accepted
+  - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-xenial-salt-2016.3 SUITE=network
+  - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-xenial-salt-2017.7 SUITE=network
+  # - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-xenial-salt-2016.3 SUITE=storage
+  # - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-xenial-salt-2017.7 SUITE=storage
+  - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-xenial-salt-2016.3 SUITE=system
+  - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-xenial-salt-2017.7 SUITE=system
+  # - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-bionic-salt-2017.7 SUITE=network
+  # - PLATFORM=epcim/salt-formulas:saltstack-ubuntu-bionic-salt-2017.7 SUITE=system
 
 before_script:
   - set -o pipefail