seize: fix used after free case

*** CID 139496:  Memory - illegal accesses  (USE_AFTER_FREE)
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

seize.c

@@ -140,10 +140,9 @@ static int freeze_processes(void)
 			if (ret == 0)
 				continue;
 
-			if (seize_catch_task(pid)) {
+			if (seize_catch_task(pid) && state == frozen) {
 				/* fails when meets a zombie */
 				fclose(f);
-				if (state == frozen)
 				goto err;
 			}
 		}