travis fix 3: - use proper env variable name for puppet version

Author: Martin Alfke

.travis.yml

@@ -21,14 +21,14 @@ matrix:
   fast_finish: true
   exclude:
     - rvm: 2.0.0
-      env: PUPPET_VERSION=3.1.1
+      env: PUPPET_GEM_VERSION=3.1.1
     - rvm: 2.1.1
-      env: PUPPET_VERSION=3.1.1
-      env: PUPPET_VERSION=3.2.4
-      env: PUPPET_VERSION=3.3.2
+      env: PUPPET_GEM_VERSION=3.1.1
+      env: PUPPET_GEM_VERSION=3.2.4
+      env: PUPPET_GEM_VERSION=3.3.2
     - rvm: 2.1.2
-      env: PUPPET_VERSION=3.1.1
-      env: PUPPET_VERSION=3.2.4
-      env: PUPPET_VERSION=3.3.2
+      env: PUPPET_GEM_VERSION=3.1.1
+      env: PUPPET_GEM_VERSION=3.2.4
+      env: PUPPET_GEM_VERSION=3.3.2
 notifications:
   email: false