Add ability to use Bundler to run puppet-lint

If Gemfile exists, use Bundler to install dependencies and
run puppet-lint check. If Gemfile is missing, fallback to previous
behavior which is to use system packages instead.

Change-Id: I6dbb9a6977b568a71225f9cbc7d5715f6deab7cd

modules/openstack_project/files/jenkins_job_builder/config/macros.yaml

@@ -85,7 +85,14 @@
               cd "$MODULE"
             fi
           fi
-          rake lint 2>&1
+          if [ -f Gemfile ]; then
+            mkdir .bundled_gems
+            export GEM_HOME=`pwd`/.bundled_gems
+            bundle install
+            bundle exec rake lint 2>&1
+          else
+            rake lint 2>&1
+          fi
 
 - builder:
     name: puppet-syntax