Added negative tests for servers

Change-Id: I6285045f023881f66e4bb42a6a188c68796ea5f5
diff --git a/storm/config.py b/storm/config.py
index 90dfed2..5ba7ef6 100644
--- a/storm/config.py
+++ b/storm/config.py
@@ -74,7 +74,7 @@
     @property
     def flavor_ref(self):
         """Valid flavorRef to use"""
-        return int(self.get("flavor_ref", 1))
+        return self.get("flavor_ref", 1)
 
     @property
     def flavor_ref_alt(self):