bug fix about splice_site type
bug fix about splice_site type

at7/ensembl,mjg17/ensembl,danstaines/ensembl,Ensembl/ensembl,muffato/ensembl,mjg17/ensembl,at7/ensembl,mjg17/ensembl,at7/ensembl,mjg17/ensembl,at7/ensembl,james-monkeyshines/ensembl,muffato/ensembl,muffato/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,Ensembl/ensembl,danstaines/ensembl,Ensembl/ensembl,willmclaren/ensembl,muffato/ensembl,willmclaren/ensembl