MariaRocks port: update results for rocksdb.col_opt_null test.

The differences are due:
- MariaDB 10.1+ assigns different DEFAULT values
  = in some cases, MariaDB's table has no default value, while
    MySQL's has '' as default.
  = BLOB/TEXT can have a default value.
- MariaDB's MTR runs tests with diffferent timezone (affects result of
  FROM_UNIXTIME())
- MySQL has removed YEAR(2). MariaDB produces warning but still creates
  the column of this type.
- Different wording in warning/error messages.