CI: remove except variables for lint and pages

Those shouldn't be needed in the current setup.
lint is already exempted in pipelines triggered via CI_JOB_TOKEN

pages: is the only triggered job currently (via an explicit
TRIGGER_TOKEN, checkupdates gets triggered via CI_JOB_TOKEN)

.gitlab-ci.yml

@@ -6,8 +6,6 @@ lint:
       - triggers
       - schedules
       - pipelines
-    variables:
-      - $CHECKUPDATES
   before_script:
     - ./tools/trigger-issuebot
     - printf "Package\x3a androguard fdroidserver python3-asn1crypto python3-ruamel.yaml\nPin\x3a release a=stretch-backports\nPin-Priority\x3a 500\n" > /etc/apt/preferences.d/debian-stretch-backports.pref
@@ -162,9 +160,6 @@ pages:
   only:
     - triggers
     - web
-  except:
-    variables:
-      - $CHECKUPDATES
   artifacts:
     paths:
       - metadata/