libgimpbase: fix #7383 GIMP loses exif data when a folder has Hebrew letters

On Windows when exporting an image saving the exif and other metadata fails
if the path or filename includes non ASCII characters.
Reason is that gexiv2 changed to using utf-8.

In the past we had to convert the filename to current locale on Windows,
but since it now also expects utf-8 there, just remove the special
handling of filename there.

(cherry picked from commit 8e1f982945)

libgimpbase/gimpmetadata.c

@@ -989,21 +989,7 @@ gimp_metadata_save_to_file (GimpMetadata  *metadata,
       return FALSE;
     }
 
-#ifdef G_OS_WIN32
-  filename = g_win32_locale_filename_from_utf8 (path);
-  /* FIXME!
-   * This call can return NULL.
-   */
-  if (! filename)
-    {
-      g_free (path);
-      g_set_error (error, GIMP_METADATA_ERROR, 0,
-                   _("Conversion of the filename to system codepage failed."));
-      return FALSE;
-    }
-#else
   filename = g_strdup (path);
-#endif
 
   g_free (path);