branches/5.1: Add a special case to handle the Duplicated Key error and return DB_ERROR instead. This is to avoid a possible SIGSEGV by mysql error handling re-entering the storage layer for dup key info without proper table handle. This is to prevent a server crash when error situation in bug #45961 "DDL on partitioned innodb tables leaves data dictionary in an inconsistent state" happens.
branches/5.1: Add a special case to handle the Duplicated Key error
and return DB_ERROR instead. This is to avoid a possible SIGSEGV
by mysql error handling re-entering the storage layer for dup key
info without proper table handle.
This is to prevent a server crash when error situation in bug
#45961 "DDL on partitioned innodb tables leaves data dictionary
in an inconsistent state" happens.

rb://157 approved by Sunny Bains.


ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,flynn1973/mariadb-aix,flynn1973/mariadb-aix,ollie314/server,flynn1973/mariadb-aix,ollie314/server,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,davidl-zend/zenddbi,natsys/mariadb_10.2,davidl-zend/zenddbi,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,slanterns/server,flynn1973/mariadb-aix,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,natsys/mariadb_10.2,natsys/mariadb_10.2,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,davidl-zend/zenddbi,flynn1973/mariadb-aix