[buildbot] ci: buildslave: fix Docker image tests

[LEDE Commits]

ynezz pushed a commit to buildbot.git, branch master:
https://git.openwrt.org/115c431809a0b7560fb8b122d49a7b7036736d8a

commit 115c431809a0b7560fb8b122d49a7b7036736d8a
Author: Petr Štetiar <ynezz at true.cz>
AuthorDate: Sat Mar 6 11:35:18 2021 +0100

    ci: buildslave: fix Docker image tests
    
    Refactoring leftover.
    
    Fixes: 70883902ecf1 ("GitLab CI integration")
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
---
 .gitlab/docker/buildslave/gitlab.yml | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/.gitlab/docker/buildslave/gitlab.yml b/.gitlab/docker/buildslave/gitlab.yml
index 960ee25..2469795 100644
--- a/.gitlab/docker/buildslave/gitlab.yml
+++ b/.gitlab/docker/buildslave/gitlab.yml
@@ -9,10 +9,11 @@ test Docker image buildslave:
   script:
     - export IMAGE_NAME="$(echo $CI_JOB_NAME | sed 's/test Docker image \(.*\)/\1/')"
     - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
-    - docker pull "$CI_REGISTRY_IMAGE/$IMAGE_NAME:$CI_COMMIT_REF_SLUG"
+    - docker pull "$CI_REGISTRY_IMAGE/$IMAGE_NAME-$BUILDBOT_VERSION:$CI_COMMIT_REF_SLUG"
     - >
       docker run --rm --env BUILDSLAVE_NAME=foo --env BUILDSLAVE_PASSWORD=XXX
-      "$CI_REGISTRY_IMAGE/$IMAGE_NAME:$CI_COMMIT_REF_SLUG" | grep "worker configured in /builder"
+      "$CI_REGISTRY_IMAGE/$IMAGE_NAME-$BUILDBOT_VERSION:$CI_COMMIT_REF_SLUG" |
+      grep "worker configured in /builder"
 
 deploy Docker image buildslave:
   stage: docker deploy