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>
diff --git a/src/stats.c b/src/stats.c
index e64bc53..d0c9750 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -254,7 +254,7 @@
 };
 
 /* one line of info */
-static THREAD_LOCAL struct field info[INF_TOTAL_FIELDS];
+THREAD_LOCAL struct field info[INF_TOTAL_FIELDS];
 
 /* description of statistics (static and dynamic) */
 static struct name_desc *stat_f[STATS_DOMAIN_COUNT];