bgpd: fix using of two pointers for struct thread_master *

bgp is using both bm->master and master pointers interchangebly
for thread manipulation.  Since they are the same thing consolidate
to one pointer.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/bgpd/bgp_damp.c b/bgpd/bgp_damp.c
index 05c30ff..359fce3 100644
--- a/bgpd/bgp_damp.c
+++ b/bgpd/bgp_damp.c
@@ -115,7 +115,7 @@
     
   damp->t_reuse = NULL;
   damp->t_reuse =
-    thread_add_timer (master, bgp_reuse_timer, NULL, DELTA_REUSE);
+    thread_add_timer (bm->master, bgp_reuse_timer, NULL, DELTA_REUSE);
 
   t_now = bgp_clock ();
 
@@ -447,7 +447,7 @@
   /* Register reuse timer.  */
   if (! damp->t_reuse)
     damp->t_reuse = 
-      thread_add_timer (master, bgp_reuse_timer, NULL, DELTA_REUSE);
+      thread_add_timer (bm->master, bgp_reuse_timer, NULL, DELTA_REUSE);
 
   return 0;
 }