BUG/MINOR: log: fix parse_log_message rfc5424 size check

In parse_log_message(), if log is rfc5424 compliant, p pointer
is incremented and size is not. However size is still used in further
checks as if p pointer was not incremented.

This could lead to logic error or buffer overflow if input buf is not
null-terminated.

Fixing this by making sure size is up to date where it is needed.

It could be backported up to 2.4.
1 file changed