Test that modules.env is complete

The test slaves that the apply tests run on have puppet modules
installed from the initial slave configuration. Delete the previously
installed modules before re-installing to ensure that the apply test
only uses the modules listed in the current change's modules.env.

Change-Id: Ie62b64133c480c05968ab554185527ac5e432858

tools/apply-test.sh

@@ -19,6 +19,8 @@ export MODULE_PATH="${ROOT}/modules:/etc/puppet/modules"
 
 export PUPPET_INTEGRATION_TEST=1
 
+sudo rm -rf /etc/puppet/modules/*
+
 cat > clonemap.yaml <<EOF
 clonemap:
   - name: '(.*?)/puppet-(.*)'