- Removed hardcoded error message from 4.1


include/my_base.h:
  Adding error message for the case when table definition has changed in storage engine
mysql-test/t/ndb_alter_table.test:
  Updated testresult to expect new error code
sql/ha_ndbcluster.cc:
  Add mapping for ndb error 284 to HA_ERR_TABLE_DEF_CHANGED, this error will occur when the table definition has been changed by another MySQL Server connected to the cluster.
  Remove hardcoded errormessage from 4.1
sql/handler.cc:
  Adding error message for the case when table definition has changed in storage engine
sql/share/errmsg.txt:
  Adding error message for the case when table definition has changed in storage engine