supermaster anti-race workaround

supermaster-race.patch

Index: packethandler.cc
===================================================================
--- packethandler.cc	(revision 2575)
+++ packethandler.cc	(working copy)
@@ -778,7 +778,13 @@
     L<<Logger::Error<<"Unable to find backend willing to host "<<p->qdomain<<" for potential supermaster "<<p->getRemote()<<endl;
     return RCode::Refused;
   }
-  db->createSlaveDomain(p->getRemote(),p->qdomain,account);
+  try {
+    db->createSlaveDomain(p->getRemote(),p->qdomain,account);
+  }
+  catch(AhuException& ae) {
+    L<<Logger::Error<<"Database error trying to create "<<p->qdomain<<" for potential supermaster "<<p->getRemote()<<": "<<ae.reason<<endl;
+    return RCode::ServFail;
+  }
   Communicator.addSuckRequest(p->qdomain, p->getRemote());  
   L<<Logger::Warning<<"Created new slave zone '"<<p->qdomain<<"' from supermaster "<<p->getRemote()<<", queued axfr"<<endl;
   return RCode::NoError;