socket: Remove useless close_pid_proc() from set_netns()

Net namespace does not act on /proc/[pid] context,
so this close is completely useless.

v4: New
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/sockets.c

@@ -778,7 +778,5 @@ int set_netns(uint32_t ns_id)
 	last_ns_id = ns_id;
 	close(nsfd);
 
-	close_pid_proc();
-
 	return 0;
 }