procfs: switch /proc/self away from proc_dir_entry

Just have it pinned in dcache all along and let procfs ->kill_sb()
drop it before kill_anon_super().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 869116c..908e974 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -506,5 +506,5 @@
 		return -ENOMEM;
 	}
 
-	return 0;
+	return proc_setup_self(s);
 }