Fixed typo

src/modules/dns-base/includes/dns-base/QDnsBase.h

@@ -55,7 +55,7 @@ namespace QDns
             MB = 7,
             MG = 8,
             MR = 9,
-            NULL = 10,
+            _NULL = 10,
             WKS = 11,
             PTR = 12,
             HINFO = 13,