Disable LOAD DATA LOCAL INFILE suport by default and
auto-enable it for the duration of one query, if the query
string starts with the word "load". In all other cases the application
should enable LOAD DATA LOCAL INFILE support explicitly.
(Based on Sergei Golubchiks 5.5 server patch)
- changed plugin API to avoid crashes: Oracle/MariaDB changed
structure several times without updating interface version.
- ABI fixes: moved additional net items to net->extension (connection
handler and com_multi buffer)