Then name of this protocol changed in commit 94531cfcbe79 ("af_unix: Add
unix_stream_proto for sockmap") because that commit added stream support
to the af_unix protocol. Renaming the existing protocol makes a ChromeOS
protocol test[1] fail now that the name has changed in
/proc/net/protocols from "UNIX" to "UNIX-DGRAM".
Let's put the name back to how it was while keeping the stream protocol
as "UNIX-STREAM" so that the procfs interface doesn't change. This fixes
the test and maintains backwards compatibility in proc.