[gimp] Revert "gitlab-ci: temporary allow distcheck job failure."

[Jehan <jehanp src gnome org>]

commit 81f9ea457c9a2d14112fa2d9dfba7b81f58df314
Author: Jehan <jehan girinstud io>
Date:   Mon Oct 26 17:12:47 2020 +0100

    Revert "gitlab-ci: temporary allow distcheck job failure."
    
    This reverts commit e869a11270b221a86d656d69ef3deb658e373e20.
    
    Mitch could reproduce the issue and made each .actions file into
    respective CLEANFILES in commit 0052803313. At least now the distcheck
    job works, so let's just make its failure forbidden again.

 .gitlab-ci.yml | 2 --
 1 file changed, 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d679192d77..2597218e74 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -143,8 +143,6 @@ gimp-autotools-debian:
     - make check
 
 gimp-distcheck-debian:
-  # Temporarily allow distcheck failure. See #5790
-  allow_failure: true
   extends: .gimp-debian-base
   script:
     - mkdir _build