Update travis jobs

The environment variables inside Gemfile changed (adopted to puppet
module generate) so we also have to modify the travis file to set the
correct environment variables when testing against specific
puppet/facter versions

.travis.yml

@@ -9,22 +9,19 @@ rvm:
   - 1.8.7
   - 1.9.3
   - 2.0.0
+  - 2.1.5
 env:
   matrix:
-    - PUPPET_GEM_VERSION="~> 2.7.0" FACTER_GEM_VERSION="~> 1.6.0"
-    - PUPPET_GEM_VERSION="~> 2.7.0" FACTER_GEM_VERSION="~> 1.7.0"
-    - PUPPET_GEM_VERSION="~> 3.0"
+    - PUPPET_VERSION="~> 2.7.0" FACTER_VERSION="~> 1.6.0"
+    - PUPPET_VERSION="~> 2.7.0" FACTER_VERSION="~> 1.7.0"
+    - PUPPET_VERSION="~> 3.0"
 matrix:
   exclude:
     - rvm: 1.9.3
-      env: PUPPET_GEM_VERSION="~> 2.7.0" FACTER_GEM_VERSION="~> 1.6.0"
-    - rvm: 1.9.3
-      env: PUPPET_GEM_VERSION="~> 2.7.0" FACTER_GEM_VERSION="~> 1.7.0"
-    - rvm: 2.0.0
-      env: PUPPET_GEM_VERSION="~> 2.7.0" FACTER_GEM_VERSION="~> 1.6.0"
+      env: PUPPET_VERSION="~> 2.7.0"
     - rvm: 2.0.0
-      env: PUPPET_GEM_VERSION="~> 2.7.0" FACTER_GEM_VERSION="~> 1.7.0"
-    - rvm: 1.8.7
-      env: PUPPET_GEM_VERSION="~> 3.2.0"
+      env: PUPPET_VERSION="~> 2.7.0"
+    - rvm: 2.1.5
+      env: PUPPET_VERSION="~> 2.7.0"
 notifications:
   email: false