parse IP proxy header also if listening on UNIX domain socket

Fixes #867

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

webdavd/webdavd.go

@@ -109,6 +109,11 @@ type Binding struct {
 }
 
 func (b *Binding) parseAllowedProxy() error {
+	if filepath.IsAbs(b.Address) && len(b.ProxyAllowed) > 0 {
+		// unix domain socket
+		b.allowHeadersFrom = []func(net.IP) bool{func(ip net.IP) bool { return true }}
+		return nil
+	}
 	allowedFuncs, err := util.ParseAllowedIPAndRanges(b.ProxyAllowed)
 	if err != nil {
 		return err