Changes the name that is used to enable a special remote.
Normally the current name is used to identify the special remote to rename, but its uuid or description
can also be used.
This is especially useful when an old special remote used a name, and now you want to use that name for a
new special remote. gitannexinitremote won't let you create a remote with a conflicting name, so rename
the old remote first.
git annex renameremote phone lost-phone
git annex initremote phone ...
This only updates the name that git-annex has stored for use by gitannexenableremote. It does not
update the git config stanza for the special remote to use the new name, but of course you can edit the
git config if you want to rename it there.