[V3] Allow the callback function to receive and log a http return code

[stevendore]

As discussed in #1916, there is an issue where the callback function will not insert the http return code into the message even though the audit log contained the correct message.
ex: callback: ModSecurity: Access denied with code %d (phase 2). Matched "Operator Rx with parameter a....
auditlog: ModSecurity: Access denied with code 200 (phase 2). Matched "Operator Rx with parameter a...

After some digging through the code for the process for the callback I found that the callback is only called through Transaction::serverLog() which contains the function ModSecurity::serverLog(m_logCbData, rm). ModSecurity has no access/reference to the Transaction::m_httpCodeReturned so it would have had to been passed by Transaction::serverLog() with this->m_httpCodeReturned to be able to be passed into the RuleMessage::log() to generate the callback message. After this patch I am able to get the http return code into the callback function message parameter.

Though I am unsure how/if props should be set or in ModSecurity::serverLog(). I am also unsure in the case that RuleMessageLogProperty is set, how to best pass the m_httpCodeReturned to the rule message or callback function.

Additionally I noticed in ModSecurity::serverLog() there might be bug due to the repeated code in the if statement.

[zimmerle]

Hi @steven-j-wojcik,

As of v3.0.3 the logging schema was restructured, as a consequence this issue was mitigated. I am sorry to close this without a merge. Thanks for the contribution. I am putting your name as a contributor for the previous change.
https://github.com/SpiderLabs/ModSecurity/blob/af137442d5389fb24c5dece2dd951a2ce9e9c9aa/CHANGES#L31-L32