Fix tox-with-tmpdir-passed-in

This is a shell, we cannot exit script. Instead exit with return value
of the script.

Change-Id: I646c89582dd029667a45c4f436b5de65586f9881

jenkins/jobs/macros.yaml

@@ -780,9 +780,9 @@
     name: tox-with-tmpdir-passed-in
     builders:
       - shell: |
-          #!/bin/bash
+          #!/bin/bash -x
           export TMPDIR={new_tmpdir_loc}
-          exit /usr/local/jenkins/slave_scripts/run-tox.sh {envlist}
+          /usr/local/jenkins/slave_scripts/run-tox.sh {envlist}
 
 - builder:
     name: assert-no-extra-files