transactions that are started before the rollback of incomplete
transactions has finished may have an inconsistent view of the
secondary indexes.

dict_index_is_sec_or_ibuf(): Auxiliary function for controlling
updates and checks of PAGE_MAX_TRX_ID: check whether an index is a
secondary index or the insert buffer tree.

page_set_max_trx_id(), page_update_max_trx_id(),
lock_rec_insert_check_and_lock(),
lock_sec_rec_modify_check_and_lock(), btr_cur_ins_lock_and_undo(),
btr_cur_upd_lock_and_undo(): Add the parameter mtr.

page_set_max_trx_id(): Allow mtr to be NULL.  When mtr==NULL, do not
attempt to write to the redo log.  This only occurs when creating a
page or reorganizing a compressed page.  In these cases, the
PAGE_MAX_TRX_ID will be set correctly during the application of redo
log records, even though there is no explicit log record about it.

btr_discard_only_page_on_level(): Preserve PAGE_MAX_TRX_ID.  This
function should be unreachable, though.

btr_cur_pessimistic_update(): Update PAGE_MAX_TRX_ID.

Add some assertions for checking that PAGE_MAX_TRX_ID is set on all
secondary index leaf pages.

rb://115 tested by Michael, fixes Issue #211