Fix insertion of GTFS data in database

Summary:
Investigate missing trip and stop bug

Fix insertion of database

-> Now the app uses 110 MB of disk space!!

Test Plan: Check it builds

Reviewers: valerio.bozzolan

Reviewed By: valerio.bozzolan

Subscribers: valerio.bozzolan, Libre BusTO

Tags: Libre BusTO

Differential Revision: https://gitpull.it/D69