Add in recognition of more complex inputs.

[danielgriggs]

There are cases where some sources are not recognised, I think because the input has a channel inside the source.

For example;

source s_syslog_tcp {
  channel {
    source {
      network( port(514) transport("tcp")
        tags("syslog_ng", "syslog_tcp", "unprocessed")
        flags(dont-store-legacy-msghdr,syslog-protocol)
      );
    };
    rewrite {
      set("tcp", value("syslog_transport"));
      set("false", value("processed"));
      set("${S_UNIXTIME}", value("unixtime"));
    };
  };
};

The only output from syslog-ng-stats is;

syslog-ng-ctl stats | grep s_syslog_tcp
source;s_syslog_tcp;;a;processed;11428093

It parses pretty much the same as a normal source.