Problem: we may create a deadlock committing changes in the mysql_alter_table() when 
LOCK_open is set. Moreover, "in some variants of the ALTER TABLE commit
happens earlier, outside of LOCK_open, in other later - inside. It's no good, a storage 
engine code that is called in between could expect a consistency - either there is a 
transaction or there is not".
Fix: move the commit to happen earlier and outside of the LOCK_open.


mysql-test/r/innodb_mysql.result:
  Fix for bug #28652: MySQL (with-debug=full) asserts when alter table operations
    - test result.
mysql-test/t/innodb_mysql.test:
  Fix for bug #28652: MySQL (with-debug=full) asserts when alter table operations
    - test case.
sql/sql_table.cc:
  Fix for bug #28652: MySQL (with-debug=full) asserts when alter table operations
    - commit moved to happen earlier in the mysql_alter_table(), 
      now we commit changes at the same time as in case when a temporary 
      table is used.