CLEANUP: deinit: release the config postparsers

These ones were not released either, it just requires to export the list
("postparsers") and it makes valgrind happy.
diff --git a/include/haproxy/cfgparse.h b/include/haproxy/cfgparse.h
index 2708f76..7c3d128 100644
--- a/include/haproxy/cfgparse.h
+++ b/include/haproxy/cfgparse.h
@@ -88,6 +88,7 @@
 	int (*func)();
 };
 
+extern struct list postparsers;
 extern int cfg_maxpconn;
 extern int cfg_maxconn;
 extern char *cfg_scope;
diff --git a/src/haproxy.c b/src/haproxy.c
index 4ae694e..02690ed 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2558,6 +2558,7 @@
 	struct post_check_fct *pcf, *pcfb;
 	struct post_proxy_check_fct *ppcf, *ppcfb;
 	struct pre_check_fct *prcf, *prcfb;
+	struct cfg_postparser *pprs, *pprsb;
 	int cur_fd;
 
 	/* At this point the listeners state is weird:
@@ -2738,6 +2739,11 @@
 		free(tff);
 	}
 
+	list_for_each_entry_safe(pprs, pprsb, &postparsers, list) {
+		LIST_DELETE(&pprs->list);
+		free(pprs);
+	}
+
 	vars_prune(&proc_vars, NULL, NULL);
 	pool_destroy_all();
 	deinit_pollers();