MINOR: log: rename 'dontloglegacyconnerr' to 'log-error-via-logformat'

Rename the 'dontloglegacyconnerr' option to 'log-error-via-logformat'
which is much more self-explanatory and readable.

Note: only legacy keywords don't use hyphens, it is recommended to
separate words with them in new keywords.
5 files changed