MINOR: contrib/prometheus-exporter: use fill_info for process dump

use `stats_fill_info` when possible to avoid duplicating code.

Signed-off-by: William Dauchy <wdauchy@gmail.com>
(cherry picked from commit 5d9b8f3c9347a1a10b86f81d70b22c3cab0e6925)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
3 files changed