.gitlab-ci.yml: Don't use after_script to terminate fuse_server

This was actually counter-productive as it prevented the ``script'' part from
terminating.

Discussed with @magiraud and @RyanHerb

See vdj#621

.gitlab-ci.yml

@@ -176,10 +176,12 @@ test_server_unit:
       - pip install -r requirements.txt
       - make -C server install_web2py_standalone
       - make -C server launch_fuse_server
-      - make unit_server
-    after_script:
-      - make -C server kill_fuse_server
-      - deactivate
+      - >
+        make unit_server
+        exit_code=$?
+        make -C server kill_fuse_server
+        deactivate
+        exit $exit_code
     only:
       - /^feature-[sw]\/.*$/
       - /^hotfix-[sw]\/.*$/
@@ -232,4 +234,4 @@ stop_deploy_review:
     - /^feature-[cw]\/.*$/
     - /^hotfix-[cw]\/.*$/
   tags:
-    - web
\ No newline at end of file
+    - web