stack/resilient: fix check if exporter failed promise

stack/resilient/pbsready-export.cfg.in

@@ -54,7 +54,7 @@ template = inline:
   EXPORTER_FEED="${notifier-exporter:log-file}"
   FAILURE_PATTERN="FAILURE"
   if [ -s "$EXPORTER_FEED" ]; then
-    tail -n 1 $EXPORTER_FEED | grep -vq FAILURE_PATTERN
+    tail -n 1 $EXPORTER_FEED | grep -vq $FAILURE_PATTERN
   fi
 rendered = ${basedirectory:promises}/exporter-status
 
@@ -83,4 +83,4 @@ recipe = slapos.cookbook:publish-early
 [slap-parameter]
 # In cron.d format (i.e things like */15 * * * * are accepted).
 resiliency-backup-periodicity =
-notify =
+notify =
\ No newline at end of file