TranscriptAdaptor::fetch_by_rnaproduct_id(): do not return explicit undef
TranscriptAdaptor::fetch_by_rnaproduct_id(): do not return explicit undef

james-monkeyshines/ensembl,Ensembl/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,muffato/ensembl,muffato/ensembl,james-monkeyshines/ensembl,muffato/ensembl,Ensembl/ensembl,muffato/ensembl,Ensembl/ensembl