Travis: Do not construct fake psql executable
Travis: Do not construct fake psql executable

This conflicts with enabling the PostgreSQL service (see ENSCORESW-3159)
and doesn't seem to be required even when the service is not enabled.

Ensembl/ensembl-hive,Ensembl/ensembl-hive,Ensembl/ensembl-hive,Ensembl/ensembl-hive