Add missing structured-data header to Syslog formatting
Add missing structured-data header to Syslog formatting

As-is the first space-delimited word of log output would get eaten as
the message id.

Signed-off-by: Daniel Farina <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@fdr.io>

heroku/logplexc,logplex/logplexc