Problem 1: main.loaddata tried to trigger an error caused by
reading files outside the vardir, by reading itself. However,
if loaddata.test is not world-readable (e.g., umask=0077),
then another error is triggered.
Fix 1: allow the other error too.
Problem 2: rpl_slave_skip and rpl_innodb_mixed_dml tried to
copy a file from mysql-test/suite/rpl/data to mysql-test/var
and then read it. That failed too if umask=0077, since the
file would not become world-readable.
Fix 2: move the files from mysql-test/suite/rpl/data to
mysql-test/std_data and update tests accordingly. Remove
the directory mysql-test/suite/rpl/data.


mysql-test/r/loaddata.result:
  Updated result file.
mysql-test/std_data/rpl_bug28618.dat:
  Moved this file to std_data.
mysql-test/std_data/rpl_mixed.dat:
  Moved this file to std_data.
mysql-test/suite/rpl/data:
  Removed directory that is now unused.
mysql-test/suite/rpl/include/rpl_mixed_dml.inc:
  The rpl_mixed.dat file has been moved. Updated the test to
  use the new location.
mysql-test/suite/rpl/r/rpl_innodb_mixed_dml.result:
  Updated result file.
mysql-test/suite/rpl/r/rpl_slave_skip.result:
  Updated result file.
mysql-test/suite/rpl/t/rpl_slave_skip.test:
  The rpl_bug28618.dat file has been moved. Updated the test
  to use the new location.
mysql-test/t/loaddata.test:
  Allow more error messages. ER_TEXTFILE_NOT_READABLE may
  happen if the file is not world-readable (which may happen,
  e.g., if the user has umask=0077).