DOmain Pointers adjusted:

When creating a new website the GlobalDNSRecord configuration defines the
hostheaders/websitepointer to be created

Various forms updated where the hostname field is set to www

GlobalDNSRecord  allows empty recordData field

To create related dns records when creating a hostheader/website pointer with
the specification of a hostname a 'A' or 'CNAME' globalDNSRecord definition
of '[host_name]' is required to create the the dns record.

WebsitePanel/Sources/WebsitePanel.EnterpriseServer/Code/Servers/ServerController.cs

@@ -2005,7 +2005,8 @@ namespace WebsitePanel.EnterpriseServer
                 }
 
                 // delete zone if required
-                DnsServerController.DeleteZone(domain.ZoneItemId);
+                if (!domain.IsDomainPointer)
+                    DnsServerController.DeleteZone(domain.ZoneItemId);
 
                 // delete domain
                 DataProvider.DeleteDomain(SecurityContext.User.UserId, domainId);