Temporarily remove 'validate' in compilePropertyBridges (Refs d2rq#194)

Work around for issue https://github.com/d2rq/d2rq/issues/194

I did not add tests, but this patch reduces the amount of test errors from 92 to 38, so it seems a move in the good direction.

Also I can now successfully run

./d2r-server chembl_postgresql.ttl

Thanks upfront for reviewing my pull request (while it is only a work around).