Syslog message without PRI header

[haimrubinstein]

Hi,

I'm using the OTEL syslog receiver that's using go-syslog.
While doing testing I noticed that the PRI header is mandatory. after some local debugging, I found this code

if (m.data)[(m.p)] == 60 {
			goto st2
		}

since multiple products sending their syslog message without the PRI header, this is blocking us.
I added a new 'MachineOption' locally to support 'no PRI' messages and tested it.

I would be more than happy to open a PR and merge it.

thanks