Removed unused functions from the handler interface.

None of the removed functions where referenced anywhere in
the rest of the code.

Non-functional code cleaning.
The following functions/code was removed from the handler
class since they where never used:
ha_index_read
ha_index_read_last
ha_reset_auto_increment
reset_auto_increment
ha_data
restart_rnd_next
rnd_same
ha_change_key_cache_param
The non-used transaction log interface and example code
was removed.

Also reset_auto_increment was removed from
engines that did not use them internally.

And finally some clean-up in ha_innobase as well:
ha_innobase::transactional_table_lock - Never used.
ha_innodb.def - Not in use since 5.5 according to Marko.