The `--modules` argument in letsencrypt toggle_hooks command is passed a list of
plinth modules as a single space-separated string. They should instead be passed
as a sequence of individual arguments.
Fixes#1520
Signed-off-by: Joseph Nuthalapati <njoseph@thoughtworks.com>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>