s3:vfs_crossrename: add back checking for errno ENOENT

s3:vfs_crossrename: add back checking for errno ENOENT

strace gives a clue: samba try to remove 'file.txt' in the dst folder but
actually it is not existed yet, and got an errno = ENOENT,

renameat(32, "file.txt", 31, "file.txt") = -1 EXDEV (Invalid cross-device link)
unlinkat(31, "file.txt", 0)             = -1 ENOENT (No such file or directory)

Commit 5c18f074be92 ("s3: VFS: crossrename. Use real dirfsp for
SMB_VFS_RENAMEAT()") seems unintentionally removed errno ENOENT checking,
so add it back could address 1st issue.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15724

Signed-off-by: Jones Syue <jonessyue@qnap.com>
Reviewed-by: Ralph Boehme <slow@samba.org>