Revert "Remove --conservative flag while installing ruby deps"

This reverts commit 05a6f1ead07015fc4e3176808af558b883e3d92e.

Change-Id: I40ab3dbd845dda978124020ed484e2ddb10ade1e
diff --git a/src/com/mirantis/mk/Ruby.groovy b/src/com/mirantis/mk/Ruby.groovy
index 05c4873..f9df3ad 100644
--- a/src/com/mirantis/mk/Ruby.groovy
+++ b/src/com/mirantis/mk/Ruby.groovy
@@ -21,8 +21,8 @@
  * Install kitchen tools
  */
 def installKitchen(kitchenInit=""){
-    sh """rbenv exec gem install bundler -v '~> 1.15.4';
-          rbenv exec gem install test-kitchen;"""
+    sh """rbenv exec gem install bundler -v '~> 1.15.4' --conservative;
+          rbenv exec gem install test-kitchen --conservative;"""
     if(kitchenInit!=""){
         sh kitchenInit
     }else{