Fix jobs w/o tempest pattern

Change-Id: I69f4679019dc72f90c0c43df10706fb57c637ab6
diff --git a/jobs/templates/test-scenarios.yml b/jobs/templates/test-scenarios.yml
index fb90131..f20a9ec 100644
--- a/jobs/templates/test-scenarios.yml
+++ b/jobs/templates/test-scenarios.yml
@@ -274,7 +274,7 @@
         name: RUN_TEST_OPTS
         trim: 'false'
     - text:
-        default: '{tempest_pattern}'
+        default: '{tempest_pattern|}'
         description: |-
           Examples: 'set=full','set=smoke' or test name.
         name: TEMPEST_PATTERN