rebuild the table.

The problem was that ROW_FORMAT clause in ALTER TABLE did not trigger
table reconstruction.

The fix is to rebuild a table if ROW_FORMAT is specified.


mysql-test/include/mix1.inc:
  Add a test case for BUG#27610: ALTER TABLE ROW_FORMAT=... does not
  rebuild the table.
mysql-test/r/innodb_mysql.result:
  Update result file.
sql/sql_table.cc:
  Rebuild a table if ROW_FORMAT was specified in ALTER TABLE.