into  example.com:/work/bug24395-v2/my50

fix for bug#24395 merged into 5.0


mysql-test/t/alter_table.test:
  Auto merged
myisam/mi_open.c:
  merge into 5.0 by using macroses available in 5.0
mysql-test/r/alter_table.result:
  manual merge
sql/sql_table.cc:
  manual merge
  Added else clause of 
  if (new_table && !new_table->file->is_view)
  This else clauses does keys management on the live table, thus we have
  to force other threads to reopen the table.