fuse: always revalidate rename target dentry

The previous commit df8629af

 ("fuse: always revalidate if exclusive
create") ensures that the dentries are revalidated on O_EXCL creates.  This
commit complements it by also performing revalidation for rename target
dentries.  Otherwise, a rename target file that only exists in kernel
dentry cache but not in the filesystem will result in EEXIST if
RENAME_NOREPLACE flag is used.

Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Signed-off-by: Zhang Tianci <zhangtianci.1997@bytedance.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>