Don't give warning for a statement that is only a comment; this is needed for
mysqldump --disable-keys to work.
Fixed unlikely caching bug when doing a join without keys. In this case
the last used field for a table always returned NULL.
Added options to make LOAD DATA LOCAL INFILE more secure.
MySQL binary release 3.23.48 for Linux contained a new glibc library,
which has serious problems under high load and Red Hat 7.2. The 3.23.49 binary
release doesn't have this problem.