fix: ensure spark entrypoint executes the post hook

Author: razvan

spark-k8s/stackable/run-spark.sh

@@ -1,10 +1,17 @@
 #!/bin/bash
 
+SPARK_CONTAINER_EXIT_CODE=0
+
 eval "$_STACKABLE_PRE_HOOK"
 
-/stackable/spark/kubernetes/dockerfiles/spark/entrypoint.sh "$@"
-result=$?
+cleanup() {
+    eval "$_STACKABLE_POST_HOOK"
+    exit $SPARK_CONTAINER_EXIT_CODE
+}
 
-eval "$_STACKABLE_POST_HOOK"
+trap 'cleanup' SIGTERM SIGINT
+
+/stackable/spark/kubernetes/dockerfiles/spark/entrypoint.sh "$@"
+SPARK_CONTAINER_EXIT_CODE=$?
 
-exit $result
+cleanup