BUG/MINOR: fix missing "log-format overrides previous 'option tcplog clf'..." detection

BUG/MINOR: fix missing "log-format overrides previous 'option tcplog clf'..." detection

In commit fd48b28315 ("MINOR: Implements new log format of option tcplog clf")
"option tcplog clf" detection was correcly added for "option tcplog" and
"option httplog", but "log-format" case was overlooked. Thus, this config
would report erroneous warning message:

  defaults
    option tcplog clf
    log-format "ok"

[WARNING]  (727893) : config : parsing [test.conf:3]: 'log-format' overrides previous 'log-format' in 'defaults' section.

No backport needed unless fd48b28315 is.