Correction for custom charts, the variable is never empty

Change-Id: Id1fdaba892d2e583b0dfe337e69c8f1cd1f51d70
diff --git a/jjb/pipeline/voltha/voltha-2.8/physical-build.groovy b/jjb/pipeline/voltha/voltha-2.8/physical-build.groovy
index fb860ea..e7a37fe 100644
--- a/jjb/pipeline/voltha/voltha-2.8/physical-build.groovy
+++ b/jjb/pipeline/voltha/voltha-2.8/physical-build.groovy
@@ -127,7 +127,7 @@
             // adding user specified helm flags at the end so they'll have priority over everything else
             localHelmFlags = localHelmFlags + " ${extraHelmFlags}"
 
-            if(openoltAdapterChart != "") {
+            if(openoltAdapterChart != "onf/voltha-adapter-openolt") {
               localHelmFlags = localHelmFlags + " --set voltha-adapter-openolt.enabled=false"
             }
 
@@ -143,7 +143,7 @@
               bbsimReplica: bbsimReplicas.toInteger(),
               ])
 
-              if(openoltAdapterChart != ""){
+              if(openoltAdapterChart != "onf/voltha-adapter-openolt"){
                 deploy_custom_oltAdapterChart(volthaNamespace, oltAdapterReleaseName, openoltAdapterChart, extraHelmFlags)
               }
           }