Using VlanId String None instead of -1

Change-Id: I2597ac37285cc3f40ad1304d668564a56a5b862f
diff --git a/core/api/src/main/java/org/onosproject/net/HostId.java b/core/api/src/main/java/org/onosproject/net/HostId.java
index 3e0d2b2..1acab00 100644
--- a/core/api/src/main/java/org/onosproject/net/HostId.java
+++ b/core/api/src/main/java/org/onosproject/net/HostId.java
@@ -79,7 +79,7 @@
         checkArgument(string.length() >= MIN_ID_LENGTH,
                       "Host ID must be at least %s characters", MIN_ID_LENGTH);
         MacAddress mac = MacAddress.valueOf(string.substring(0, MAC_LENGTH));
-        VlanId vlanId = VlanId.vlanId(Short.parseShort(string.substring(MAC_LENGTH + 1)));
+        VlanId vlanId = VlanId.vlanId(string.substring(MAC_LENGTH + 1));
         return new HostId(mac, vlanId);
     }