…ixes rclone#7478

Before this change, it was not always possible to delete an empty source root
directory during `rclone move`. Furthermore, the behavior was inconsistent based
on whether the move was performed server-side or via the fallback to copy +
delete.

After this change, a --leave-root flag is added to control whether --delete-empty-src-
dirs deletes an empty src root. (It has no effect if --delete-empty-src-dirs=false or
if the src root isn't empty.)

Note that --leave-root defaults to false, which is arguably a breaking change,
although also arguably not, since the prior behavior was already inconsistent
(the root was, in fact, still deleted for server-side moves without filters.)
Defaulting to false also makes it consistent with the identical option in
`rclone rmdirs`.

This setting should be particularly helpful for users wanting to rename a
directory in place.

Note that both --delete-empty-src-dirs and --leave-root are effectively ignored for
server-side directory move operations without filters, which always use the
equivalent of --delete-empty-src-dirs=true --leave-root=false. (This is not a change,
but was not previously documented.)

…ixes rclone#7478

Before this change, it was not always possible to delete an empty source root
directory during `rclone move`. Furthermore, the behavior was inconsistent based
on whether the move was performed server-side or via the fallback to copy +
delete.

After this change, a --leave-root flag is added to control whether --delete-empty-src-
dirs deletes an empty src root. (It has no effect if --delete-empty-src-dirs=false or
if the src root isn't empty.)

Note that --leave-root defaults to false, which is arguably a breaking change,
although also arguably not, since the prior behavior was already inconsistent
(the root was, in fact, still deleted for server-side moves without filters.)
Defaulting to false also makes it consistent with the identical option in
`rclone rmdirs`.

This setting should be particularly helpful for users wanting to rename a
directory in place.

Note that both --delete-empty-src-dirs and --leave-root are effectively ignored for
server-side directory move operations without filters, which always use the
equivalent of --delete-empty-src-dirs=true --leave-root=false. (This is not a change,
but was not previously documented.)