exit(1) if the zone had errors

src/com/verisignlabs/dnssec/cl/VerifyZone.java

@@ -147,14 +147,14 @@ public class VerifyZone extends CLBase
     if (errors > 0)
     {
       System.out.println("zone did not verify.");
+      System.exit(1);
     }
     else
     {
       System.out.println("zone verified.");
-    }
-
       System.exit(0);
     }
+  }
 
   public static void main(String[] args)
   {