the latter while not IANA registered is apparently used in places. to
cheaply support it we now configure the protocol file for both protocol
'smb' and 'cifs' and installing two protocol files. they are still both
backed by the same plugin and otherwise the same.
code-wise this also required adjustments to the URL validation tech as
it has hardcoded checks for smb schemes.
FIXED-IN: 19.12.3
BUG: 327295