[CI] Fix for bm cleanup

Task: PRODX-40255

Change-Id: I61090070380eb7e2c3d0218658ce73120d06faeb
diff --git a/src/com/mirantis/mk/KaasUtils.groovy b/src/com/mirantis/mk/KaasUtils.groovy
index 9f63070..07b28a2 100644
--- a/src/com/mirantis/mk/KaasUtils.groovy
+++ b/src/com/mirantis/mk/KaasUtils.groovy
@@ -123,7 +123,7 @@
     def enableOSDemo = true
     def enableBMDemo = true
     def enablebmCoreDemo = env.ALLOW_BM_CORE_ON_DEMAND ? env.ALLOW_BM_CORE_ON_DEMAND.toBoolean() : false
-    def bmCoreCleanup = env.BM_CORE_CLEANUP ? env.BM_CORE_CLEANUP : true
+    def bmCoreCleanup = env.BM_CORE_CLEANUP ? env.BM_CORE_CLEANUP.toBoolean() : true
     def enableArtifactsBuild = true
     def bmDeployType = env.BM_DEPLOY_TYPE ? env.BM_DEPLOY_TYPE.toString() : 'virtual'
     def openstackIMC = env.OPENSTACK_CLOUD_LOCATION ? env.OPENSTACK_CLOUD_LOCATION : 'us'