* net/tramp-smb.el (tramp-smb-errors): Add error messages.

* net/tramp-smb.el (tramp-smb-errors): Add error messages.
(tramp-smb-file-name-handler-alist): Add handler for
`copy-directory', `expand-file-name', `set-file-modes'.
(tramp-smb-handle-copy-directory)
(tramp-smb-handle-expand-file-name)
(tramp-smb-handle-set-file-modes): New defuns.
(tramp-smb-handle-copy-file): Handle KEPP-DATE.
(tramp-smb-handle-file-attributes): Simplify check for retrieving
entry.
(tramp-smb-handle-insert-directory): Don't flush the cache.
(tramp-smb-maybe-open-connection): Check for samba client and
server versions.