Set irrelevant-files for bashate job

This commit sets the tempest-irrelevant-files-2 for the bashate job. We
just need to run the job when we change bash scripts. Currently, bash
scripts are located in the tools/ directory only. So,
"tempest-irrelevant-files-2" is better than "tempest-irrelevant-files".

Change-Id: I0f55ffaa844736056769f1fbeca82fc0cb0a9a86
diff --git a/.zuul.yaml b/.zuul.yaml
index d893483..8e49c91 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -694,7 +694,8 @@
         - tempest-full-test-account-no-admin-py3:
             voting: false
             irrelevant-files: *tempest-irrelevant-files
-        - openstack-tox-bashate
+        - openstack-tox-bashate:
+            irrelevant-files: *tempest-irrelevant-files-2
     gate:
       jobs:
         - tempest-slow-py3: