VLAN wildcard is null, unlike others. REST API now returns correct devices...

VLAN wildcard is null, unlike others. REST API now returns correct devices across all VLANS when VLAN is unspecified.

src/main/java/net/floodlightcontroller/devicemanager/web/AbstractDeviceResource.java

@@ -61,7 +61,7 @@ public abstract class AbstractDeviceResource extends ServerResource {
                     get(IDeviceService.class.getCanonicalName());  
                 
         MacAddress macAddress = MacAddress.NONE;
-        VlanVid vlan = VlanVid.ZERO;
+        VlanVid vlan = null; /* must be null for don't care */
         IPv4Address ipv4Address = IPv4Address.NONE;
         IPv6Address ipv6Address = IPv6Address.NONE;
         DatapathId switchDPID = DatapathId.NONE;