Respect setgid bit of the upper directory in Tramp

Respect setgid bit of the upper directory in Tramp

* doc/misc/trampver.texi:
* lisp/net/trampver.el: Change version to "2.4.2-pre".

* lisp/net/tramp.el: Bump version to 2.4.2-pre.
(tramp-set-file-uid-gid): Respect setgid bit of the upper directory.
(tramp-default-file-modes, tramp-handle-insert-file-contents)
(tramp-mode-string-to-int, tramp-make-tramp-temp-file):
* lisp/net/tramp-adb.el (tramp-adb-handle-file-local-copy)
(tramp-adb-handle-write-region):
* lisp/net/tramp-sh.el (tramp-do-copy-or-rename-file-directly)
(tramp-sh-handle-write-region): Use octal constants.