Improve commands::query::search_libelle

Summary:
Sets an exit code if no record has been found.

Fixes strange indent.

This is a follow-up for 5357130c.

Test Plan: target/debug/fantoir-datasource query xaos ; echo $?

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D2751