Do not overwrite error value

internal/model/rwfolder.go

@@ -643,7 +643,7 @@ func (p *rwFolder) deleteDir(file protocol.FileInfo) {
 	if err == nil || os.IsNotExist(err) {
 		// It was removed or it doesn't exist to start with
 		p.dbUpdates <- file
-	} else if _, err = os.Lstat(realName); err != nil && !os.IsPermission(err) {
+	} else if _, err := os.Lstat(realName); err != nil && !os.IsPermission(err) {
 		// We get an error just looking at the directory, and it's not a
 		// permission problem. Lets assume the error is in fact some variant
 		// of "file does not exist" (possibly expressed as some parent being a