Bug#29547 mysql-test-run to retrieve warnings for failed command  - Run "SHOW WARNINGS" when mysqltest fails and display all but the    last warning(since it's the same as "last error") on stderr  - Fix typo
Bug#29547 mysql-test-run to retrieve warnings for failed command
 - Run "SHOW WARNINGS" when mysqltest fails and display all but the
   last warning(since it's the same as "last error") on stderr
 - Fix typo


client/mysqltest.c:
  - Display any warnings produced prior to the error that caused
  mysqltest to die.
  - Fix typo "cur_con" -> "con_slot"
  - Move initialization of the "cur_con" pointer to just before it's
    initialized  so it can be used to check if a connection to mysql
    exist.

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