[FIX] Use Postgres 9.3 in Travis
[FIX] Use Postgres 9.3 in Travis

Fixes failing Travis build and removes the lock_timeout error found in
the structure.sql as this was added in Postgres 9.3

ministryofjustice/scs_appraisals,ministryofjustice/scs_appraisals,ministryofjustice/scs_appraisals