Add --force switch to mmm_control move_role

[Pascal Hofmann]

If the passive master is in state REPLICATION_FAIL/REPLICATION_DELAY it should be possible to move the active_master role to this host by using something like "mmm_control move_role --force ...".

A big warning message should be displayed!

(Idea from Istvan Podor in #mmm on irc.freenode.net)

[Walter Heck (walterheck)]

Since it is very closely related I figured i'd add this here:

--force should also make it possible to move roles when you have a preferred role. currently you cannot move a writer role away from the preferred host, which should be possible, although accompanied by a big fat warning :)

[Pascal Hofmann (pascalhofmann)]

It is only possible if at least one of the replication checks has failed on each master hosts. Otherwise mmmd_mon would just move it backwards. Best way would be to remove the preferred host from the config file and restart the monitor.