Make sh call syntax more consistent

Fix one call that looks unlike any other sh() call. Incidentally,
this is also precisely where execute_test stops executing in current
pipeline runs.

Fixes: 9f66e3f9 ("[VOL-5177] - verify_voltha-openolt-adapter_sanity-test failure")
Signed-off-by: Roger Luethi <roger@opennetworking.org>
Change-Id: I790bab3ccab4bb544ecf3bfd34a036fcf8112bab
diff --git a/jjb/pipeline/voltha/bbsim-tests.groovy b/jjb/pipeline/voltha/bbsim-tests.groovy
index 1a7953c..8228dcb 100644
--- a/jjb/pipeline/voltha/bbsim-tests.groovy
+++ b/jjb/pipeline/voltha/bbsim-tests.groovy
@@ -311,7 +311,7 @@
             // -----------------------------------------------------------------------
             // -----------------------------------------------------------------------
             sh(label  : 'while-true-port-forward',
-               """
+               script : """
       JENKINS_NODE_COOKIE="dontKillMe" _TAG="voltha-voltha-api" bash -c "while true; do kubectl port-forward --address 0.0.0.0 -n ${volthaNamespace} svc/voltha-voltha-api 55555:55555; done"&
       JENKINS_NODE_COOKIE="dontKillMe" _TAG="voltha-infra-etcd" bash -c "while true; do kubectl port-forward --address 0.0.0.0 -n ${infraNamespace} svc/voltha-infra-etcd 2379:2379; done"&
       JENKINS_NODE_COOKIE="dontKillMe" _TAG="voltha-infra-kafka" bash -c "while true; do kubectl port-forward --address 0.0.0.0 -n ${infraNamespace} svc/voltha-infra-kafka 9092:9092; done"&