Rename Prometheus alerts for consistency

Change-Id: I088d59606aa9a9c0f86baf86227cff698c8eafcd
diff --git a/keepalived/meta/prometheus.yml b/keepalived/meta/prometheus.yml
index 6fe2186..5172ace 100644
--- a/keepalived/meta/prometheus.yml
+++ b/keepalived/meta/prometheus.yml
@@ -2,7 +2,7 @@
 {%- if cluster.get('enabled', False) %}
 server:
   alert:
-    ProcstatRunningKeepalived:
+    KeepalivedProcessDown:
       if: >-
         procstat_running{process_name="keepalived"} == 0
       {% raw %}