restore: Kill CR_STATE_RESTORE_SHARED

Looks like this separate stage is not needed. The scripts
involved in ns restore are synchronized with existing stages
like this:

criu:                    root task:
ROOT_TASK stage
                         <appear>
"setup-ns" script
PREPARE_NAMESPACES
                         prepare_namespace()
"post-setup-ns" script
FORKING
                         restore_task_mnt_ns()
                         <everything else>

which seems to be OK.
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/cr-restore.c

@@ -127,7 +127,6 @@ static inline int stage_participants(int next_stage)
 		return 0;
 	case CR_STATE_ROOT_TASK:
 	case CR_STATE_PREPARE_NAMESPACES:
-	case CR_STATE_RESTORE_SHARED:
 		return 1;
 	case CR_STATE_FORKING:
 		return task_entries->nr_tasks + task_entries->nr_helpers;
@@ -1569,9 +1568,6 @@ static int restore_task_with_children(void *_arg)
 
 		if (root_prepare_shared())
 			goto err;
-
-		if (restore_finish_stage(task_entries, CR_STATE_RESTORE_SHARED) < 0)
-			goto err;
 	}
 
 	if (restore_task_mnt_ns(current))
@@ -1970,15 +1966,12 @@ static int restore_root_task(struct pstree_item *init)
 			goto out_kill;
 	}
 
-	timing_start(TIME_FORK);
-	ret = restore_switch_stage(CR_STATE_RESTORE_SHARED);
-	if (ret < 0)
-		goto out_kill;
-
 	ret = run_scripts(ACT_POST_SETUP_NS);
 	if (ret)
 		goto out_kill;
 
+	timing_start(TIME_FORK);
+
 	ret = restore_switch_stage(CR_STATE_FORKING);
 	if (ret < 0)
 		goto out_kill;

criu/include/restorer.h

@@ -207,7 +207,6 @@ enum {
 	 * will be used to clean up remap files.
 	 */
 	CR_STATE_PREPARE_NAMESPACES,
-	CR_STATE_RESTORE_SHARED,
 	CR_STATE_FORKING,
 	CR_STATE_RESTORE,
 	CR_STATE_RESTORE_SIGCHLD,