Exclude record_archiver from the one-by-one tests

Because an error prevent creation of res.partner records in the tests due the
'mail' addon adding a required 'notification_email_send' field. This addon does
not depend on 'mail' so the test violates the not-null constraint.

The tests are passing in the normal builds anyway.

.travis.yml

@@ -16,7 +16,7 @@ env:
   - VERSION="7.0" LINT_CHECK=1
   - VERSION="7.0" ODOO_REPO="odoo/odoo" LINT_CHECK=0
   - VERSION="7.0" ODOO_REPO="OCA/OCB" LINT_CHECK=0
-  - VERSION="7.0" UNIT_TEST="1" LINT_CHECK=0
+  - VERSION="7.0" UNIT_TEST="1" LINT_CHECK=0 EXCLUDE=record_archiver
 
 virtualenv:
   system_site_packages: true