Several points of synchronization during ALTER TABLE COPY looked identical
in the progress report query. Besides, if its the late lock upgrade stage,
the data would be:
STAGE   0
MAX_STAGE       0
PROGRESS        0.000

which looks irrelevant.

This patch moves thd_progress_deinit call after the last lock upgrade.

Also, for online alter, if there is nothing to replicate, the
progress and max_progress values would be 0, which discard the result data
on the side of sql_show, see processlist_callback in sql_show.cc.
So now the minimal max_progress will be 1. To avoid 0% progress in the
report, minimax progress value is also set to 1, so we will see 100% if
there's nothing to replicate.