Fix transcript update

Created by: mira13

Description

Transcript db id must be 0 if no transcripts set. It's a bugfix for my PR to update gene stable id. It was not visible until i fixed travis build in neighbour branch

Use case

When no transcript set, not transcript id is 1, that is wrong.

Benefits

Bugfix

Testing

All tests are fine, they pass

Have you run the entire test suite and no regression was detected?

yes