* net/tramp-gvfs.el (top): Require url-util.

* net/tramp-gvfs.el (top): Require url-util.
(tramp-gvfs-mount-point): Removed.
(tramp-gvfs-stringify-dbus-message, tramp-gvfs-send-command): New
defuns.
(with-tramp-dbus-call-method): Format trace message.
(tramp-gvfs-handle-copy-file, tramp-gvfs-handle-rename-file):
Implement backup call, when operation on local files fails.  Use
progress reporter.  Flush properties of changed files.
(tramp-gvfs-handle-make-directory): Make more traces.
(tramp-gvfs-url-file-name): Hexify file name in url.
(tramp-gvfs-fuse-file-name): Take also prefix (like dav shares)
into account for the resulting file name.
(tramp-gvfs-handler-askquestion): Return dummy mountpoint, when
the answer is "no".  See `tramp-gvfs-maybe-open-connection'.
(tramp-gvfs-handler-mounted-unmounted)
(tramp-gvfs-connection-mounted-p): Test also for new mountspec
attribute "default_location".  Set "prefix" property.
(tramp-gvfs-mount-spec): Return both prefix and mountspec.
(tramp-gvfs-maybe-open-connection): Test, whether mountpoint
exists.  Raise an error, if not (due to a corresponding answer
"no" in interactive questions, for example).