Before this change an `rclone lsjson --encrypted` command where
additional `--crypt-` parameters were supplied on the command line:
rclone lsjson --crypt-description XXX --encrypted secret:
Produced an error like this:
Failed to lsjson: ListJSON failed to load config for crypt remote: config name contains invalid characters...
This was due to an incorrect lookup of the crypt config to create the
encrypted mapping.
Fixes#7833