Remove Emacs 23 compat code from Tramp

Remove Emacs 23 compat code from Tramp

* doc/misc/tramp.texi (Remote processes): Don't mention
Emacs 24 explicitely.
(Frequently Asked Questions): Remove Emacs 23 from
compatibility list.

* lisp/net/tramp.el:
* lisp/net/tramp-adb.el:
* lisp/net/tramp-cache.el:
* lisp/net/tramp-gvfs.el:
* lisp/net/tramp-sh.el:
* lisp/net/tramp-smb.el: Replace compat function calls.

* lisp/net/tramp-compat.el (remote-file-name-inhibit-cache)
(tramp-compat-condition-case-unless-debug)
(tramp-compat-copy-file, tramp-compat-copy-directory)
(tramp-compat-delete-file, tramp-compat-delete-directory)
(tramp-compat-process-live-p): Remove them.

* lisp/net/trampver.el: Make version check fit for Emacs 24.