Update handlers_data.go

Under Windows: no change
Under Linux: Fix directory creation with no read/write permissions that failed the creation of save data dump

server/channelserver/handlers_data.go

@@ -240,7 +240,7 @@ func dumpSaveData(s *Session, data []byte, suffix string) {
 		_, err := os.Stat(dir)
 		if err != nil {
 			if os.IsNotExist(err) {
-				err = os.Mkdir(dir, os.ModeDir)
+				err = os.Mkdir(dir, os.ModePerm)
 				if err != nil {
 					s.logger.Warn("Error dumping savedata, could not create folder")
 					return