zdtm: add MNTNS_ZDTM macro to fix initialization

With this macro we can easily declare struct mntns_zdtm variables with
all lists properly initiallized. Let's use it in mount_complex_sharing
as without it we can have segfault on error path when accessing
uninitialized list pointers.

Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>

test/zdtm/lib/mountinfo.h

@@ -24,6 +24,14 @@ struct mntns_zdtm {
 	struct list_head sharing_groups_list;
 };
 
+#define MNTNS_ZDTM_INIT(name)                                                    \
+	{                                                                        \
+		.mountinfo_list = LIST_HEAD_INIT(name.mountinfo_list),           \
+		.topology_list = LIST_HEAD_INIT(name.topology_list),             \
+		.sharing_groups_list = LIST_HEAD_INIT(name.sharing_groups_list), \
+	}
+#define MNTNS_ZDTM(name) struct mntns_zdtm name = MNTNS_ZDTM_INIT(name)
+
 struct sharing_group {
 	int shared_id;
 	int master_id;

test/zdtm/static/mount_complex_sharing.c

@@ -212,7 +212,8 @@ static int mount_loop(void)
 
 int main(int argc, char **argv)
 {
-	struct mntns_zdtm mntns_before, mntns_after;
+	MNTNS_ZDTM(mntns_before);
+	MNTNS_ZDTM(mntns_after);
 	int ret = 1;
 
 	test_init(argc, argv);