[gimp] Revert "desktop: add an <icon> tag in appdata."

[Jehan Pagès <jehanp src gnome org>]

commit 0c4cbbfffa8c2d7d98f9b4602726990bdd0b8374
Author: Jehan <jehan girinstud io>
Date:   Sat Apr 28 18:03:07 2018 +0200

    Revert "desktop: add an <icon> tag in appdata."
    
    This reverts commit e5dcd8095773e2e09734bc4e28dca12fab40c2db.
    So apparently this is not the right fix (for the original flatpak issue)
    and we already have the icon specified in the desktop file.
    Let's just cancel this commit until we understand better the problem.

 desktop/org.gimp.GIMP.appdata.xml.in.in |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/desktop/org.gimp.GIMP.appdata.xml.in.in b/desktop/org.gimp.GIMP.appdata.xml.in.in
index 722ab0a..6a02df9 100644
--- a/desktop/org.gimp.GIMP.appdata.xml.in.in
+++ b/desktop/org.gimp.GIMP.appdata.xml.in.in
@@ -13,7 +13,6 @@
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>GPL-3.0+ AND LGPL-3.0+</project_license>
   <_name>GNU Image Manipulation Program</_name>
-  <icon type="stock">gimp</icon>
   <_summary>Create images and edit photographs</_summary>
   <description>
     <_p>