ci: Add work-around for podman-push permission issue

For some reason, podman recently started to fail to read files
in non-world-readable directories:

https://gitlab.gnome.org/Infrastructure/Infrastructure/-/issues/1247

As long as it happens with stuff we don't actually need, the
work-around is to just remove the offending files.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3513>

.gitlab-ci.yml

@@ -138,6 +138,12 @@ variables:
                       mutter mutter-devel \
                       gnome-shell
 
+      # Work-around for podman-push aborting on permission issue
+      # https://gitlab.gnome.org/Infrastructure/Infrastructure/-/issues/1247
+      rm -rf /etc/pki/pesign/
+      chmod -R a+rX /opt/mutter/$MUTTER_USER
+      chmod -R a+rX /var/lib/gdm
+
       # Ensure that we mark the project clone dir as safe directory
       git config --system --add safe.directory "$CI_PROJECT_DIR"