Jenkinsfile: always clean build directories

Jenkinsfile

@@ -44,7 +44,7 @@ PGPORT=`python3 -c 'import struct; import socket; s=socket.socket(); s.setsockop
                 utils.mail_notify(currentBuild, env, 'ci+jenkins-authentic2-wallonie-connect@entrouvert.org')
             }
         }
-        success {
+        cleanup {
             sh "rm -rf ${env.TMPDIR}"
             cleanWs()
         }