Keep error handling system using message_die for SQL exceptions

By default, Keruald Database is configured to throw exceptions
when a SQL error occurs.

The current handling error code checks the false value,
and calls message_die() with SQL_ERROR code. This mechanism
requires to configure Keruald Database to use legacy mode.

This is a transitional change pending implementation
of an exception handler.

Test Plan:

• Before: error logged, 500 served
• After: explicit error message

Differential Revision: https://devcentral.nasqueron.org/D3790