[fix][core] allow on-demand vsphere demo run

- allows trigger nighlty job from UI by hand
- allows triggering vsphere demo from external repos

PRODX-8681

Change-Id: I70ce47b3666eb129424cac3f5259351edec4cbe0
diff --git a/src/com/mirantis/mk/KaasUtils.groovy b/src/com/mirantis/mk/KaasUtils.groovy
index a2c2365..87471c4 100644
--- a/src/com/mirantis/mk/KaasUtils.groovy
+++ b/src/com/mirantis/mk/KaasUtils.groovy
@@ -65,7 +65,7 @@
     // optional demo deployment customization
     def awsOnDemandDemo = env.ALLOW_AWS_ON_DEMAND ? env.ALLOW_AWS_ON_DEMAND.toBoolean() : false
     def awsOnRhelDemo = false
-    def vsphereOnDemandDemo = false
+    def vsphereOnDemandDemo = env.ALLOW_VSPHERE_ON_DEMAND ? env.ALLOW_VSPHERE_ON_DEMAND.toBoolean() : false
     def enableOSDemo = true
     def enableBMDemo = true