Fix without env kitchen calling

Change-Id: I5d39b593e194333048da1d08f30bc4a365537089
diff --git a/src/com/mirantis/mk/Ruby.groovy b/src/com/mirantis/mk/Ruby.groovy
index 91604db..4b5813f 100644
--- a/src/com/mirantis/mk/Ruby.groovy
+++ b/src/com/mirantis/mk/Ruby.groovy
@@ -64,7 +64,7 @@
     if(environment && environment != ""){
         return sh(script: "${environment} rbenv exec bundler exec kitchen ${cmd}", returnStdout: true)
     }else{
-        return sh("rbenv exec bundler exec kitchen ${cmd}", returnStdout: true)
+        return sh(script: "rbenv exec bundler exec kitchen ${cmd}", returnStdout: true)
     }
 }