Bug 1233813 - Fix mDNS bug in resolving services with no TXT records. r=schien

netwerk/dns/mdns/libmdns/nsDNSServiceInfo.cpp

@@ -196,7 +196,7 @@ NS_IMETHODIMP
 nsDNSServiceInfo::SetAttributes(nsIPropertyBag2* aAttributes)
 {
   mAttributes = aAttributes;
-  mIsAttributesSet = true;
+  mIsAttributesSet = aAttributes ? true : false;
   return NS_OK;
 }