[fix][core] multiregion trigger conditional rules

PRODX-6926

Change-Id: I5d751e285b5a2fc8ddfd15d683d3c782a714eb35
diff --git a/src/com/mirantis/mk/KaasUtils.groovy b/src/com/mirantis/mk/KaasUtils.groovy
index 297b9f0..f22d358 100644
--- a/src/com/mirantis/mk/KaasUtils.groovy
+++ b/src/com/mirantis/mk/KaasUtils.groovy
@@ -175,7 +175,7 @@
     def supportedRegionalProviders = ['os']
 
     def clusterTypes = ''
-    if (keyword.contains('multiregion')) {
+    if (keyword.toString().contains('multiregion')) {
         common.infoMsg('Multiregion definition configured via gerrit keyword trigger')
         clusterTypes = keyword[0][0].split('multiregion')[1].replaceAll('[\\[\\]]', '').trim().split(',')
     } else {