This makes the code clearer and reduces race conditions, as the monitor
could be writing SERVER->status while a router is reading it. Also,
the time during which the SERVER struct is locked drops to a fraction.
The master down verification through slaves won't work with this commit. It needs to be
redesigned to handle multiple slave connections or removed. Also, only the first row of
slave status data is used by the monitor, so multiple slave connections are still
incorrectly handled.
5.1 to 5.3 are officially not supported anymore, so support can be removed from
the monitor. This allows removing the config parameter "mysql51_replication".
MASTER_GTID_WAIT uses gtid_slave_pos when comparing to the target gtid. This creates
problems with multi-domain gtids. It's simpler to just query the server for its
gtids repeatedly. Also, the method is now in MariaDBServer.
Renamed the two gtid-classes to better match MariaDB documentation. One
domain-server-sequence-combination is now a "Gtid", as these identify
a transaction. A "GtidList" contains a list of Gtid:s for handling multi-domain
server variables composed of multiple comma separated Gtid:s.
Removed unused methods and renamed some existing ones. Moved the Gtid-code
to its own file.
The operations between Gtid:s are now more complicated so the class implements
them instead of the monitor. The Old Gtid-container has been renamed
GtidTriplet, and only stores the values for one triplet.
Also, the QueryResult integer reading method now only reads non-negative integers
since the server rarely returns negative values. This frees negative values for
indicating parsing error(s).
Gtid-class was moved back to utility.hh/.cc because the QueryResult-class requires it.
