CI: drop /tmp/artifacts upload to Gitlab

Contents of this folder are uploaded to S3 with shutzbot/upload_artifacts.sh
Also fixing epel installation in the mentioned script.

.gitlab-ci.yml

@@ -666,7 +666,7 @@ Manifest-diff:
     GIT_DEPTH: 500
   artifacts:
     paths:
-      - "/tmp/artifacts"
+      - manifests.diff
 
 SCHEDULED_CLOUD_CLEANER:
   stage: cleanup

schutzbot/upload_artifacts.sh

@@ -10,7 +10,7 @@ ARTIFACTS=${ARTIFACTS:-/tmp/artifacts}
 function greenprint {
   echo -e "\033[1;32m[$(date -Isecond)] ${1}\033[0m"
 }
-
+source /etc/os-release
 # s3cmd is in epel, add if it's not present
 if [[ $ID == rhel || $ID == centos ]] && ! rpm -q epel-release; then
     curl -Ls --retry 5 --output /tmp/epel.rpm \

test/cases/diff-manifests.sh

@@ -2,9 +2,6 @@
 
 set -euo pipefail
 
-artifacts="/tmp/artifacts"
-mkdir -p "${artifacts}"
-
 # Colorful output.
 function greenprint {
     echo -e "\033[1;32m[$(date -Isecond)] ${1}\033[0m"
@@ -90,10 +87,10 @@ if (( err == 0 )); then
 fi
 
 greenprint "Manifests differ"
-echo "${diff}" > "${artifacts}/manifests.diff"
+echo "${diff}" > "manifests.diff"
 greenprint "Saved diff in job artifacts"
 
-artifacts_url="${CI_JOB_URL}/artifacts/browse/ci-artifacts"
+artifacts_url="${CI_JOB_URL}/artifacts/browse"
 
 cat > "${review_data_file}" << EOF
 {"body":"⚠️ This PR introduces changes in at least one manifest (when comparing PR HEAD ${head} with the ${basebranch} merge-base ${mergebase}).  Please review the changes.  The changes can be found in the [artifacts of the \`Manifest-diff\` job [0]](${artifacts_url}) as \`manifests.diff\`.\n\n${merge_base_fail}[0] ${artifacts_url}","event":"COMMENT"}