Added parallel switch to kitchen test functions

Change-Id: I5c08bdf042f65c7f2decc122881953886fc5bb29
diff --git a/src/com/mirantis/mk/Ruby.groovy b/src/com/mirantis/mk/Ruby.groovy
index 31876c3..939bf2c 100644
--- a/src/com/mirantis/mk/Ruby.groovy
+++ b/src/com/mirantis/mk/Ruby.groovy
@@ -34,8 +34,10 @@
 
 /**
  * Run kitchen tests in tests/integration
+ * @param environment kitchen environment (optional can be empty)
+ * @param parallel run kitchen test suites in parallel (optional, default true)
  */
-def runKitchenTests(environment=""){
+def runKitchenTests(environment="", parallel = true){
     def common = new com.mirantis.mk.Common()
     def kitchenTests=runKitchenCommand("list -b", environment)
     if(kitchenTests && kitchenTests != ""){
@@ -47,7 +49,11 @@
                 runKitchenCommand("converge " + testSuite, environment)
             }
         }
-        parallel kitchenTestRuns
+        if(parallel){
+            parallel kitchenTestRuns
+        }else{
+            common.serial(kitchenTestRuns)
+        }
         runKitchenCommand("destroy", environment)
         runKitchenCommand("verify -t tests/integration", environment)
     }else{
@@ -67,7 +73,4 @@
     }else{
         return sh(script: "rbenv exec bundler exec kitchen ${cmd}", returnStdout: true)
     }
-}
-
-
-
+}
\ No newline at end of file