unsetting voltha1.6 argument to siab builds

Change-Id: I2b18c08910915b714639ae428e6eea74f87af205
diff --git a/jjb/pipeline/siab.groovy b/jjb/pipeline/siab.groovy
index 7029bf7..8d39454 100644
--- a/jjb/pipeline/siab.groovy
+++ b/jjb/pipeline/siab.groovy
@@ -39,7 +39,7 @@
       steps {
         sh """
             pushd $WORKSPACE/automation-tools/seba-in-a-box
-	    make SEBAVALUES=configs/seba-ponsim-voltha-1.6.yaml
+            make
             popd
             """
             }