gitlab-ci: don't use before_script in job templates

When gitlab prepares a job to run, it checks out the repository with a
non-root user, and spawns a container that runs as root, with some UID
mapping that makes the files be owned by root in the
container. However, our pipelines run as a nont-root user.

Commit bde165f7ad (.gitlab-ci.yml: update Docker image to use) updated
the docker image that is used to run in our pipelines.

That new image includes a git version that is stricter about the
ownership of the git tree it is acting in: git aborts in error when the
user running it does not own the repository.

We use `git ls-tree` quite a lot in our check-{flake8,package,symbols}
rules, so they all fail (in various ways).

To fix this, we either need to fix the ownership or tell git to ignore
the situation. In either case, we'll need to run a scriptlet before all
our jobs.

Gitlab-ci allows to provide a global before_script, that is inherited by
all jobs. However, some of our jobs already declare a before_script, and
that would shadow the global before_script.

There is no technical reason to do our before_script separately from
the actual script, so we move the code from the before_scripts to the
corresponding scripts.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Cc: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/misc/gitlab-ci.yml.in

@@ -23,9 +23,8 @@
         - utils/check-symbols
 
 .defconfig_check:
-    before_script:
-        - DEFCONFIG_NAME=$(echo ${CI_JOB_NAME} | sed -e 's,_check$,,g')
     script:
+        - DEFCONFIG_NAME=$(echo ${CI_JOB_NAME} | sed -e 's,_check$,,g')
         - echo "Configure Buildroot for ${DEFCONFIG_NAME}"
         - make ${DEFCONFIG_NAME}
         - support/scripts/check-dotconfig.py .config configs/${DEFCONFIG_NAME}
@@ -44,10 +43,9 @@
       }
 
 .defconfig_base:
-    before_script:
+    script:
         - DEFCONFIG_NAME=${CI_JOB_NAME}
         - OUTPUT_DIR=output
-    script:
         - echo "Configure Buildroot for ${DEFCONFIG_NAME}"
         - make ${DEFCONFIG_NAME}
         - ./support/scripts/check-dotconfig.py .config ./configs/${DEFCONFIG_NAME}
@@ -72,13 +70,12 @@
             - runtime-test.log
 
 .runtime_test_base:
-    before_script:
-        - TEST_CASE_NAME=${CI_JOB_NAME}
     # Keep build directories so the rootfs can be an artifact of the job. The
     # runner will clean up those files for us.
     # Multiply every emulator timeout by 10 to avoid sporadic failures in
     # elastic runners.
     script:
+        - TEST_CASE_NAME=${CI_JOB_NAME}
         - echo "Starting runtime test ${TEST_CASE_NAME}"
         - ./support/testing/run-tests -o test-output/ -d test-dl/ -k --timeout-multiplier 10 ${TEST_CASE_NAME}
     artifacts:
@@ -91,9 +88,8 @@
 
 .test_pkg:
     stage: build
-    before_script:
-        - OUTPUT_DIR=${CI_JOB_NAME}
     script:
+        - OUTPUT_DIR=${CI_JOB_NAME}
         - echo "Configure Buildroot for ${OUTPUT_DIR}"
         - make O=${OUTPUT_DIR} syncconfig
         - make O=${OUTPUT_DIR} savedefconfig