http: supersede domainless cookies

The scope of cookies without a domain is limited to the current server.
The current logic is always wrong because either it's the same server
and the new cookie should supersede the old one, or it's a different
server and the old cookie should not be sent. This logic is still far
from RFC-compliant, but at least it should get it right some of the time.

modules/access/http.c

@@ -1720,8 +1720,10 @@ static void cookie_append( vlc_array_t * cookies, char * cookie )
 
         assert( current_cookie_name );
 
-        bool is_domain_matching = ( cookie_domain && current_cookie_domain &&
-                                         !strcmp( cookie_domain, current_cookie_domain ) );
+        bool is_domain_matching = (
+                      ( !cookie_domain && !current_cookie_domain ) ||
+                      ( cookie_domain && current_cookie_domain &&
+                        !strcmp( cookie_domain, current_cookie_domain ) ) );
 
         if( is_domain_matching && !strcmp( cookie_name, current_cookie_name )  )
         {