Fixed passing JSON to pepper

Change-Id: Id28f88c9b34720d8991abb9f6d878de7b8d675cf
diff --git a/src/com/mirantis/mk/Salt.groovy b/src/com/mirantis/mk/Salt.groovy
index a613799..53a06d8 100644
--- a/src/com/mirantis/mk/Salt.groovy
+++ b/src/com/mirantis/mk/Salt.groovy
@@ -664,7 +664,7 @@
     def python = new com.mirantis.mk.Python()
     def dataStr = new groovy.json.JsonBuilder(data).toString()
 
-    def pepperCmd = "pepper -c ${venv}/pepperrc --make-token -x ${venv}/.peppercache --json \'${dataStr}\'"
+    def pepperCmd = "pepper -c ${venv}/pepperrc --make-token -x ${venv}/.peppercache --json '${dataStr}'"
 
     if (venv) {
         output = python.runVirtualenvCommand(venv, pepperCmd)