Ticket 48420: change severity of some messages related to "keep alive" entries

Bug Description:
	"keep alive" entries are used to prevent fractional replication
	to evaluate several times the same skipped updates. (see https://fedorahosted.org/389/ticket/48266)

	This entry is created on the fly when two many evaluated
	updates have been skipped. This is a quite common situation
	and the creation of such entry is not a FATAL error

Fix Description:
	Change the log level to replication level

https://fedorahosted.org/389/ticket/48420

Reviewed by: Ludwig Krispenz (thanks Ludwig)

Platforms tested: F17

Flag Day: no

Doc impact: no

(cherry picked from commit 6788445974404398bc02da8fa105b06514e8a450)
(cherry picked from commit 17bb0688b9249693da0bda239fb7c3b35aa8e1c9)
(cherry picked from commit 50405f8b8349757cfbe2e9f14a22b9e674b93787)

ldap/servers/plugins/replication/repl5_replica.c

@@ -487,7 +487,7 @@ replica_subentry_check(Slapi_DN *repl_root, ReplicaId rid)
                     "Need to create replication keep alive entry <cn=%s %d,%s>\n", KEEP_ALIVE_ENTRY, rid, slapi_sdn_get_dn(repl_root));
             rc = replica_subentry_create(repl_root, rid);
         } else {
-            slapi_log_error(SLAPI_LOG_FATAL, repl_plugin_name,
+            slapi_log_error(SLAPI_LOG_REPL, repl_plugin_name,
                     "replication keep alive entry <cn=%s %d,%s> already exists\n", KEEP_ALIVE_ENTRY, rid, slapi_sdn_get_dn(repl_root));
             rc = 0;
         }