Remove extra quotes on cvp-spt job parameter

Change-Id: Icba45cfd956762c39e999e9edbb4af98cd93e274
Fixed-Bug:#PROD-32018(PROD:32018)
diff --git a/jenkins/client/job/validate.yml b/jenkins/client/job/validate.yml
index 0abb96b..a99c583 100644
--- a/jenkins/client/job/validate.yml
+++ b/jenkins/client/job/validate.yml
@@ -419,7 +419,7 @@
               default: |
                 envs:
                   - tests_set=''
-                  - image_name='Ubuntu'
+                  - image_name=Ubuntu
                   - networks=10.101.0.0/24
               description: 'YAML context with additional parameters. Additional params: HW_NODES, CMP_HOSTS, salt_timeout, skipped_nodes, nova_timeout, iperf_prep_string, IMAGE_SIZE_MB'
         cvp-shaker: