Drop Icinga DB special case

... once there’s a tag to be used and pinned to until next tag (as with other mods). I.e. remove:

Lines 17 to 19 in 1c41f9c

    
           icingadb) 
        
           	REF=2c0662c420617712bd26234da550dcf8d4afcdb8 # v1.0.0-rc1+ 
        
           	;;

This special case makes the current icinga/icingaweb2:master container pretty much unusable (at least if the icingadb module is enabled), instead of the sidebar, you only see the following error message:

Fatal error: Declaration of Icinga\Module\Icingadb\Model\Behavior\ReRoute::rewriteCondition(Icinga\Data\Filter\FilterExpression $expression, $relation = NULL) must be compatible with ipl\Orm\Contract\RewriteFilterBehavior::rewriteCondition(ipl\Stdlib\Filter\Condition $condition, $relation = NULL) in /usr/share/icingaweb2/modules/icingadb/library/Icingadb/Model/Behavior/ReRoute.php on line 10

Replacing this by REF=master resolves this issue for me. I don't know why this was pinned to a specific commit in the first place though.

	icingadb)
	REF=2c0662c420617712bd26234da550dcf8d4afcdb8 # v1.0.0-rc1+
	;;