ci(shellcheck): fix exit code propagation (reanahub#425)

Return properly the exit code status of shellcheck command when looping
through shell script files.

etc/job_wrapper.sh

@@ -7,15 +7,16 @@
 # around by dumping command to a
 # temporary wrapper file.
 tmpjob=$(mktemp -p .)
-chmod +x $tmpjob
+chmod +x "$tmpjob"
 echo "command to execute:"
 # $@ input is base64 encoded string of command to execute
+# shellcheck disable=SC2068,SC2294
 eval $@
 
-echo "$@" "|bash" > $tmpjob
-bash $tmpjob
+echo "$@" "|bash" > "$tmpjob"
+bash "$tmpjob"
 res=$?
-rm $tmpjob
+rm "$tmpjob"
 
 if [ $res != 0 ]; then
     echo "[Error] Execution failed with error code: $res"

run-tests.sh

@@ -76,7 +76,7 @@ check_commitlint () {
 }
 
 check_shellcheck () {
-    find . -name "*.sh" -exec shellcheck {} \;
+    find . -name "*.sh" -exec shellcheck {} \+
 }
 
 check_pydocstyle () {