Jenkinsfile: use a TMPDIR for tox (#31437)

Jenkinsfile

@@ -3,9 +3,13 @@
 pipeline {
     agent any
     options { disableConcurrentBuilds() }
+    environment {
+        TMPDIR = "/tmp/$BUILD_TAG"
+    }
     stages {
         stage('Unit Tests') {
             steps {
+                sh "mkdir ${env.TMPDIR}"
                 sh './jenkins.sh'
             }
             post {
@@ -35,6 +39,7 @@ pipeline {
     }
     post {
         always {
+            sh "rm -rf ${env.TMPDIR}"
             script {
                 utils = new Utils()
                 utils.mail_notify(currentBuild, env, 'admin+jenkins-authentic@entrouvert.com')

tox.ini

@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-toxworkdir = {env:TMPDIR:/tmp}/tox-{env:USER}/authentic/{env:BRANCH_NAME:}
+toxworkdir = {env:TMPDIR:/tmp}/tox-{env:USER}/authentic/
 envlist = py27-coverage-{dj18,dj111}-authentic-{pg,sqlite}-{oldldap,},py27-coverage-{dj18,dj111}-rbac-{pg,sqlite}
 
 [testenv]