The virtual member function handler::reset_auto_increment(ulonglong)
is only ever invoked by the default implementation of the virtual
member function handler::truncate().

Because ha_innobase::truncate() overrides handler::truncate() without
ever invoking handler::truncate(), some InnoDB member functions are
never called.

ha_innobase::innobase_reset_autoinc(), ha_innobase::reset_auto_increment():
Removed (unreachable code).

ha_innobase::delete_all_rows(): Removed. The default implementation
handler::delete_all_rows() works just as fine.