libsmbc doesn't presently support smb://[ABCD::DCBA]/ uris because it
has very opinionated colon parsing. as a workaround we convert hosts
that are ipv6 addresses to their windows ipv6 literal representation.
that is basically s/:/-/g and s/%/s/g and appending .ipv6-literal.net.
BUG: 417682
FIXED-IN: 20.04