GA Release v1.4.543

GTID:

- Added "reset-master-gtid-remove-own-uuid" command
- ResetMasterGTIDOperation supports removal of self-UUID entries
- setGTIDPurged respects --noop
- Repoint() makes up a non-existent binlog file name when log file is
empty (can be cause when switching to/from GTID with error)