ignore_unsupported_options will mask registered object's error message

if ignore_unsupported_options is true, it will ignore the NotSupported status returned by:
https://github.com/facebook/rocksdb/blob/806d8916da26dfc82ed361a56dde790132f0d6a6/include/rocksdb/utilities/customizable_util.h#L64
Not sure whether this option is used to support ROCKSDB_LITE here:
https://github.com/facebook/rocksdb/blob/806d8916da26dfc82ed361a56dde790132f0d6a6/include/rocksdb/utilities/customizable_util.h#L66-L68
But if the registered FactoryFunc failed to create an object, and returns null, then upper layer logic will receive nullptr + Status::OK, and also the errormsg in FactoryFunc is lost, which seems not quite reasonable.