When setting the default syslog maxMessageSize, use an upper limit of 65000
for the cases where the automatic detection goes over this limit. UDP
messages are limited to 65536 bytes, but that includes the UDP headers
themselves, so the value of 65000 is used instead (this is the value
that used to be statically used)
Merge pull request #165 from ericdahl/syslog-maxsize-limit

Limit the maximumMessageSize for SyslogAppender to be 65000