Simplify Travis config and fix ChefDK 2.0 failures

.travis.yml

@@ -4,7 +4,7 @@ dist: trusty
 addons:
   apt:
     sources:
-      - chef-stable-trusty
+      - chef-current-trusty
     packages:
       - chefdk
 
@@ -26,15 +26,15 @@ env:
 
 before_script:
   - sudo iptables -L DOCKER || ( echo "DOCKER iptables chain missing" ; sudo iptables -N DOCKER )
-  - eval "$(/opt/chefdk/bin/chef shell-init bash)"
-  - /opt/chefdk/embedded/bin/chef --version
-  - /opt/chefdk/embedded/bin/cookstyle --version
-  - /opt/chefdk/embedded/bin/foodcritic --version
+  - eval "$(chef shell-init bash)"
+  - chef --version
+  - cookstyle --version
+  - foodcritic --version
 
-script: KITCHEN_LOCAL_YAML=.kitchen.dokken.yml /opt/chefdk/embedded/bin/kitchen verify ${INSTANCE}
+script: KITCHEN_LOCAL_YAML=.kitchen.dokken.yml kitchen verify ${INSTANCE}
 
 matrix:
   include:
     - script:
-      - /opt/chefdk/bin/chef exec delivery local all
+      - chef exec delivery local all
       env: UNIT_AND_LINT=1