auth: dnsbackend: replace a bare NULL

diff --git a/pdns/dnsbackend.hh b/pdns/dnsbackend.hh
index c086e2ddf76cfac47ec28562e5c1dab02796351d..3d68b7d8626b20a9f1ccb6d9cded9224771e7ea4 100644 (file)
--- a/pdns/dnsbackend.hh
+++ b/pdns/dnsbackend.hh
@@ -46,7 +46,7 @@ class DNSPacket;
 class DNSBackend;  
 struct DomainInfo
 {
-  DomainInfo() : last_check(0), backend(NULL), id(0), notified_serial(0), serial(0), kind(DomainInfo::Native) {}
+  DomainInfo() : last_check(0), backend(nullptr), id(0), notified_serial(0), serial(0), kind(DomainInfo::Native) {}
 
   DNSName zone;
   time_t last_check;