Replaced json slurper with classic one

Change-Id: Ie09ce67fbf18deb7f6bcb7ce8586895b5f49c436
diff --git a/src/com/mirantis/mk/Common.groovy b/src/com/mirantis/mk/Common.groovy
index 1789bd7..d4b817c 100644
--- a/src/com/mirantis/mk/Common.groovy
+++ b/src/com/mirantis/mk/Common.groovy
@@ -1,8 +1,8 @@
 package com.mirantis.mk
 
-import groovy.json.JsonSlurper
 import static groovy.json.JsonOutput.prettyPrint
 import static groovy.json.JsonOutput.toJson
+import groovy.json.JsonSlurperClassic
 /**
  *
  * Common functions
@@ -405,7 +405,7 @@
  */
 def parseJSON(jsonString){
    def m = [:]
-   def lazyMap = new JsonSlurper().parseText(jsonString)
+   def lazyMap = new JsonSlurperClassic().parseText(jsonString)
    m.putAll(lazyMap)
    return m
 }