Revert "bgpd: Lower BGP's default keepalive/holdtime to 3s/9s"

This reverts commit f89b09be92bed03b1e5add55dc14ef92e94c52e1.

Martin Winter has reported reliability issues in testing on some platforms.
We need a more comprehensive way to deal with defaults and updating them, e.g.
profiles of some kind.

Defer this change till after next release.
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 5be5a19..7665d9d 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -743,8 +743,8 @@
 
 /* BGP timers default value.  */
 #define BGP_INIT_START_TIMER                     5
-#define BGP_DEFAULT_HOLDTIME                     9
-#define BGP_DEFAULT_KEEPALIVE                    3
+#define BGP_DEFAULT_HOLDTIME                   180
+#define BGP_DEFAULT_KEEPALIVE                   60 
 #define BGP_DEFAULT_EBGP_ROUTEADV               30
 #define BGP_DEFAULT_IBGP_ROUTEADV                5
 #define BGP_CLEAR_CONNECT_RETRY                 20