Fixing physical build pipeline

Change-Id: I69de1b4beb49ceefdd1cbbd9f4e91b65d4f62127
diff --git a/jjb/pipeline/voltha/master/physical-build.groovy b/jjb/pipeline/voltha/master/physical-build.groovy
index b3b6c71..c791e91 100644
--- a/jjb/pipeline/voltha/master/physical-build.groovy
+++ b/jjb/pipeline/voltha/master/physical-build.groovy
@@ -109,7 +109,7 @@
             "--set onos-classic.individualOpenFlowNodePorts=true "
 
             def bbsimReplica = 0
-            if (installBBSim) {
+            if (installBBSim.toBoolean()) {
               bbsimReplica = 1
               extraHelmFlags = extraHelmFlags + " --set onu=${onuNumber},pon=${ponNumber} "
             }