lint: Add missing set -ex to ci/lint/06_script.sh

This is needed for the container-entrypoint.sh

Also, remove unused `source` from ci/lint_run_all.sh, since it is the
last step.

ci/lint/06_script.sh

@@ -6,6 +6,8 @@
 
 export LC_ALL=C
 
+set -ex
+
 if [ -n "$LOCAL_BRANCH" ]; then
   # To faithfully recreate CI linting locally, specify all commits on the current
   # branch.

ci/lint_run_all.sh

@@ -8,4 +8,5 @@ export LC_ALL=C.UTF-8
 
 set -o errexit; source ./ci/test/00_setup_env.sh
 set -o errexit; source ./ci/lint/04_install.sh
-set -o errexit; source ./ci/lint/06_script.sh
+set -o errexit
+./ci/lint/06_script.sh