Fixed some bugs when using undo of VARCHAR fields

Fixed bug in undo_delete
Fixed wrong error output from maria_check


include/my_base.h:
  Added marker if we have null fields in table
mysql-test/r/maria.result:
  checksum in maria now ignore null fields that are null
sql/sql_table.cc:
  Ignore null fields that are now
  (Before enabling this, we have to change MyISAM to also skip null fields)
storage/maria/ma_blockrec.c:
  More logging
  After merge fixes
  Fixed some bugs when using undo of VARCHAR fields
  Fixed bug in undo_delete (We can't use info->rec_buff here as this is used in write_block_record())
storage/maria/ma_blockrec.h:
  ma_recordpos_to_dir_entry changed to return uint
storage/maria/ma_check.c:
  Fixed wrong output in case of errors
storage/maria/ma_create.c:
  Set share.base.pack_reclength more correct for block record
  Delete support for RAID
storage/maria/ma_open.c:
  Don't calculate checksum fields with value NULL
storage/maria/ma_test1.c:
  Fixed output from -v for VARCHAR keys
storage/maria/ma_test_recovery.expected:
  Update results after adding new printf
  New checksums (because we now ignore nulls)
  Some file lengths are different, but think they are ok (didn't have time to investigate)
storage/myisam/ha_myisam.cc:
  Fixed comment
storage/myisam/mi_test1.c:
  Fixed bug

sql/sql_table.cc

@@ -7082,6 +7082,10 @@ bool mysql_checksum_table(THD *thd, TABLE_LIST *tables,
 	    for (uint i= 0; i < t->s->fields; i++ )
 	    {
 	      Field *f= t->field[i];
+#ifdef NOT_YET
+              if (f->is_real_null(0))
+                continue;
+#endif
 	      if ((f->type() == MYSQL_TYPE_BLOB) ||
                   (f->type() == MYSQL_TYPE_VARCHAR))
 	      {