Consider return value: pSess->pEngine->onSyslogRcv2

[alorbach]

https://github.com/rsyslog/librelp/blob/60fb51342f7ffd614bf7df9bfbea21b08c6e4f3e/src/scsyslog.c#L60 https://github.com/rsyslog/librelp/blob/60fb51342f7ffd614bf7df9bfbea21b08c6e4f3e/src/scsyslog.c#L63

https://github.com/rsyslog/librelp/blob/60fb51342f7ffd614bf7df9bfbea21b08c6e4f3e/src/scsyslog.c#L70

Should we consider checking the return value from onSyslogRcv2/onSyslogRcv callbacks? At the moment the return status of those callbacks is ignored.