gitlab-ci: drop centos:7 tests

CentOS7 uses gcc-4.8, which have various problems and working around
them is getting more cumbersome.

Also, CentOS7 is ancient by now. It's time. Drop it.

.gitlab-ci.yml

@@ -57,11 +57,11 @@ variables:
   #
   # This is done by running `ci-fairy generate-template` and possibly bumping
   # ".default_tag".
-  ALPINE_TAG:  'tag-d831870051be'
-  CENTOS_TAG:  'tag-62b1e9c63f3f'
-  DEBIAN_TAG:  'tag-c531494bb725'
-  FEDORA_TAG:  'tag-62b1e9c63f3f'
-  UBUNTU_TAG:  'tag-c531494bb725'
+  ALPINE_TAG:  'tag-15ad9771f66e'
+  CENTOS_TAG:  'tag-01eb3016c31d'
+  DEBIAN_TAG:  'tag-5b69abc7e7b7'
+  FEDORA_TAG:  'tag-01eb3016c31d'
+  UBUNTU_TAG:  'tag-5b69abc7e7b7'
 
   ALPINE_EXEC: 'bash .gitlab-ci/alpine-install.sh'
   CENTOS_EXEC: 'bash .gitlab-ci/fedora-install.sh'
@@ -327,28 +327,6 @@ tier3:debian:testing@prep:
     FDO_DISTRIBUTION_EXEC: $DEBIAN_EXEC
   when: manual
 
-tier2:centos:7.5.1804@prep:
-  extends:
-    - .fdo.container-build@centos
-  stage: prep
-  variables:
-    GIT_STRATEGY: none
-    FDO_DISTRIBUTION_VERSION: '7.5.1804'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-    FDO_DISTRIBUTION_EXEC: $CENTOS_EXEC
-  when: manual
-
-tier2:centos:7.9.2009@prep:
-  extends:
-    - .fdo.container-build@centos
-  stage: prep
-  variables:
-    GIT_STRATEGY: none
-    FDO_DISTRIBUTION_VERSION: '7.9.2009'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-    FDO_DISTRIBUTION_EXEC: $CENTOS_EXEC
-  when: manual
-
 tier2:centos:8.1.1911@prep:
   extends:
     - .fdo.container-build@centos
@@ -393,39 +371,6 @@ tier2:centos:stream9@prep:
     FDO_DISTRIBUTION_EXEC: $CENTOS_EXEC
   when: manual
 
-tier3:centos:7.6.1810@prep:
-  extends:
-    - .fdo.container-build@centos
-  stage: prep
-  variables:
-    GIT_STRATEGY: none
-    FDO_DISTRIBUTION_VERSION: '7.6.1810'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-    FDO_DISTRIBUTION_EXEC: $CENTOS_EXEC
-  when: manual
-
-tier3:centos:7.7.1908@prep:
-  extends:
-    - .fdo.container-build@centos
-  stage: prep
-  variables:
-    GIT_STRATEGY: none
-    FDO_DISTRIBUTION_VERSION: '7.7.1908'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-    FDO_DISTRIBUTION_EXEC: $CENTOS_EXEC
-  when: manual
-
-tier3:centos:7.8.2003@prep:
-  extends:
-    - .fdo.container-build@centos
-  stage: prep
-  variables:
-    GIT_STRATEGY: none
-    FDO_DISTRIBUTION_VERSION: '7.8.2003'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-    FDO_DISTRIBUTION_EXEC: $CENTOS_EXEC
-  when: manual
-
 tier3:centos:8.2.2004@prep:
   extends:
     - .fdo.container-build@centos
@@ -727,30 +672,6 @@ t_debian:testing:
   needs:
     - "tier3:debian:testing@prep"
 
-t_centos:7.5.1804:
-  extends:
-    - .build@template
-    - .fdo.distribution-image@centos
-    - .nm_artifacts_debug
-  stage: tier2
-  variables:
-    FDO_DISTRIBUTION_VERSION: '7.5.1804'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-  needs:
-    - "tier2:centos:7.5.1804@prep"
-
-t_centos:7.9.2009:
-  extends:
-    - .build@template
-    - .fdo.distribution-image@centos
-    - .nm_artifacts_debug
-  stage: tier2
-  variables:
-    FDO_DISTRIBUTION_VERSION: '7.9.2009'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-  needs:
-    - "tier2:centos:7.9.2009@prep"
-
 t_centos:8.1.1911:
   extends:
     - .build@template
@@ -799,42 +720,6 @@ t_centos:stream9:
   needs:
     - "tier2:centos:stream9@prep"
 
-t_centos:7.6.1810:
-  extends:
-    - .build@template
-    - .fdo.distribution-image@centos
-    - .nm_artifacts_debug
-  stage: tier3
-  variables:
-    FDO_DISTRIBUTION_VERSION: '7.6.1810'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-  needs:
-    - "tier3:centos:7.6.1810@prep"
-
-t_centos:7.7.1908:
-  extends:
-    - .build@template
-    - .fdo.distribution-image@centos
-    - .nm_artifacts_debug
-  stage: tier3
-  variables:
-    FDO_DISTRIBUTION_VERSION: '7.7.1908'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-  needs:
-    - "tier3:centos:7.7.1908@prep"
-
-t_centos:7.8.2003:
-  extends:
-    - .build@template
-    - .fdo.distribution-image@centos
-    - .nm_artifacts_debug
-  stage: tier3
-  variables:
-    FDO_DISTRIBUTION_VERSION: '7.8.2003'
-    FDO_DISTRIBUTION_TAG: $CENTOS_TAG
-  needs:
-    - "tier3:centos:7.8.2003@prep"
-
 t_centos:8.2.2004:
   extends:
     - .build@template

.gitlab-ci/config.yml

@@ -61,8 +61,6 @@ distributions:
   - name: centos
     tier: 2
     versions:
-      - '7.5.1804'
-      - '7.9.2009'
       - '8.1.1911'
       - '8.3.2011'
       - 'stream8'
@@ -70,9 +68,6 @@ distributions:
   - name: centos
     tier: 3
     versions:
-      - '7.6.1810'
-      - '7.7.1908'
-      - '7.8.2003'
       - '8.2.2004'
   - name: alpine
     tier: 2