Print information if net_clear() skipped bytes (As this otherwise hides critical timeing bugs)
Added DBUG_ASSERT if we get packets out of order
mysql_change_user() could on error send multiple packets, which caused mysql_client_test to randomly fail


include/errmsg.h:
  Added more descriptive error message of why statement was automaticly dropped
libmysql/client_settings.h:
  Added more descriptive error message of why statement was automaticly dropped
libmysql/errmsg.c:
  Added more descriptive error message of why statement was automaticly dropped
libmysql/libmysql.c:
  Added more descriptive error message of why statement was automaticly dropped
sql-common/client.c:
  Added more descriptive error message of why statement was automaticly dropped
sql/net_serv.cc:
  Print information if net_clear() skipped bytes (As this otherwise hides critical timeing bugs)
  Added DBUG_ASSERT if we get packets out of order
sql/sql_class.cc:
  We need to set killed to NOT_KILLED after cleanup() if we want to continue using THD
  (If not, the connection will be closed after the current stmt)
sql/sql_parse.cc:
  mysql_change_user() could on error send multiple packets, which caused mysql_client_test to randomly fail
tests/mysql_client_test.c:
  More DBUG information
  Better usage of --silent
  Always print 'OK' the same way.
  Disable test_bug17667 if run outside of mysql-test-run