Remove Tramp "obex" and "synce" methods

Remove Tramp "obex" and "synce" methods

* doc/misc/tramp.texi (GVFS based methods): Remove `obex' and `synce'.

* etc/NEWS: Mention obsolete Tramp "obex" and "synce" methods.

* lisp/net/tramp-gvfs.el (tramp-gvfs-methods):
Remove "obex" and "synce".
(top): Do not add defaults for "obex" and "synce".
(tramp-bluez-service, tramp-bluez-interface-manager)
(tramp-bluez-interface-adapter)
(tramp-bluez-discover-devices-timeout, tramp-bluez-discovery)
(tramp-bluez-devices, tramp-hal-service, tramp-hal-path-manager)
(tramp-hal-interface-manager, tramp-hal-interface-device)
(tramp-bluez-address, tramp-bluez-device)
(tramp-bluez-list-devices, tramp-bluez-property-changed)
(tramp-bluez-device-found, tramp-bluez-parse-device-names)
(tramp-synce-list-devices, tramp-synce-parse-device-names): Remove.
(tramp-gvfs-handler-mounted-unmounted)
(tramp-gvfs-connection-mounted-p, tramp-gvfs-mount-spec): Do not
handle "obex" and "synce".