command line clients.

Postfix covering other mysql standard clients like mysql_upgrade,
mysqlbinlog, mysqlcheck, mysqlimport, mysqlshow and mysqlslap.


client/client_priv.h:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients
  
  Added an entry for 'default-auth' option.
client/mysql.cc:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients
  
  Updated the id entry for default_auth option.
client/mysql_upgrade.c:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
client/mysqladmin.cc:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients
  
  Updated the id entry for default_auth option.
client/mysqlbinlog.cc:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
client/mysqlcheck.c:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
client/mysqldump.c:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients
  
  Updated the id entry for default_auth option.
client/mysqlimport.c:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
client/mysqlshow.c:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
client/mysqlslap.c:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
mysql-test/r/plugin_auth.result:
  Added test case for Bug#58139 for mysql_upgrade.
mysql-test/t/plugin_auth.test:
  Added test case for Bug#58139 for mysql_upgrade.