This fixes a bug that when you use mysqldump --no-create-info to generate a dump that you want to merge with an existing table,
you can get an innodb table with duplicated unique keys.
Patch orignally by Eric Bergen.


client/mysqldump.c:
  Only use UNIQUE_CHECKS=0 for tables that are created.
  This solves the issue that you can't get duplicate unique keys when merging two dumps.
mysql-test/r/mysqldump.result:
  Test for mysqldump --no-create-info