RFC5424 specifies a version number (currently 1) after the facility and
severity in a syslog message (e.g. <7>1 TIMESTAMP ...).  This causes
rsyslog to fail to parse syslog message because the rest of the message
is not fully compliant with RFC5424.

For the widest compatibility, drop the version (messages are in the
RFC3164 BSD syslog format (e.g. <7>TIMESTAMP ...). Have tested this with
syslog-ng, rsyslog and syslogd.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7036050