missing method for filter_associations :condition should be assumed to be the same as condition returning false

[elrayle]

Example: If a new filter_association is added for a work that has generic_files as members that can be of many different specific classes of generic_files, then each of the specific classes have to implement the condition method. To avoid having to define the condition method multiple times, I propose the following change to the processing of conditions...

FAIL: if it gets ‘method missing’
FAIL: if condition method returns anything but true
PASS: if condition method returns true

[elrayle]

Currently, with 'method missing', the condition processing code raises an error instead of simply failing to pass the condition.