The MONTHNAME/DAYNAME functions
returns binary string, so the LOWER/UPPER functions
are not effective on the result of MONTHNAME/DAYNAME call.
Character set of the MONTHNAME/DAYNAME function
result has been changed to connection character set.
Problem: replication of LC_TIME_NAMES didn't work.
Thus, INSERTS or UPDATES using date_format() always
worked with en_US on the slave side.
Fix: adding ONE_SHOT implementation for LC_TIME_NAMES.