bgpd: use ATTR_FLAG_BIT() for BGP_ATTR_ values

* bgp_attr.c: this UNSET_FLAG()s are bogus. I did a quick review and
  I think that they could not cause any bug anyway.

Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
Acked-by: Feng Lu <lu.feng@6wind.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index cbf2902..feb073c 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -645,21 +645,21 @@
   /* aspath refcount shoud be decrement. */
   if (attr->aspath)
     aspath_unintern (&attr->aspath);
-  UNSET_FLAG(attr->flag, BGP_ATTR_AS_PATH);
+  UNSET_FLAG(attr->flag, ATTR_FLAG_BIT (BGP_ATTR_AS_PATH));
   
   if (attr->community)
     community_unintern (&attr->community);
-  UNSET_FLAG(attr->flag, BGP_ATTR_COMMUNITIES);
+  UNSET_FLAG(attr->flag, ATTR_FLAG_BIT (BGP_ATTR_COMMUNITIES));
   
   if (attr->extra)
     {
       if (attr->extra->ecommunity)
         ecommunity_unintern (&attr->extra->ecommunity);
-      UNSET_FLAG(attr->flag, BGP_ATTR_EXT_COMMUNITIES);
+      UNSET_FLAG(attr->flag, ATTR_FLAG_BIT (BGP_ATTR_EXT_COMMUNITIES));
       
       if (attr->extra->cluster)
         cluster_unintern (attr->extra->cluster);
-      UNSET_FLAG(attr->flag, BGP_ATTR_CLUSTER_LIST);
+      UNSET_FLAG(attr->flag, ATTR_FLAG_BIT (BGP_ATTR_CLUSTER_LIST));
       
       if (attr->extra->transit)
         transit_unintern (attr->extra->transit);