Third attempt to fix the Jenkins build. Needs to clean up the venv environment and also specify a vagnant box version that works with frameio tests

Change-Id: I22a0fac1d300372b6678e10f877d4c68affaa2f8
diff --git a/Jenkinsfile b/Jenkinsfile
index 8318e34..25ad933 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -7,6 +7,9 @@
             stage 'Bring up voltha dev vm'
             sh 'vagrant up voltha'
 
+            stage 'Remove the pre-created venv-linux'
+            sh 'vagrant ssh -c "rm -rf /cord/incubator/voltha/venv-linux"'
+
             stage 'Build voltha'
             sh 'vagrant ssh -c "cd /cord/incubator/voltha && source env.sh && make fetch && make build" voltha'