ValueConditionBuilder to return FalseCondition for non-supported DataItem type

- `SMWDIGeoCoord`
- `SMW\DIConcept`

Avoids an exception for when `null` is returned which surfaced during the encounter with [0].

[0] https://github.com/SemanticMediaWiki/SemanticMaps/pull/29
Merge pull request #598 from SemanticMediaWiki/valuecond-falsecond

ValueConditionBuilder to return FalseCondition for non-supported DataIte...