[gimp] app: fix the test for XCF version with off-canvas guides.

[Jehan <jehanp src gnome org>]

commit 5e68a953ee6b7450d84b7e71f86cf0e545c6bd4f
Author: Jehan <jehan girinstud io>
Date:   Mon Mar 29 17:58:36 2021 +0200

    app: fix the test for XCF version with off-canvas guides.

 app/core/gimpimage.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/app/core/gimpimage.c b/app/core/gimpimage.c
index 23b22a1d8c..c97cb43d94 100644
--- a/app/core/gimpimage.c
+++ b/app/core/gimpimage.c
@@ -2834,8 +2834,8 @@ gimp_image_get_xcf_version (GimpImage    *image,
           if (position < 0 ||
               (gimp_guide_get_orientation (list->data) == GIMP_ORIENTATION_HORIZONTAL &&
                position > gimp_image_get_height (image)) ||
-              /* vertical guide. */
-               position > gimp_image_get_width (image))
+              (gimp_guide_get_orientation (list->data) == GIMP_ORIENTATION_VERTICAL &&
+               position > gimp_image_get_width (image)))
             {
               ADD_REASON (g_strdup_printf (_("Off-canvas guides "
                                              "added in %s"), "GIMP 3.0.0"));