Merge isisd into the Quagga's framework:
  - add privs support
  - use misc quagga's definitions
  - make it compile"able"
  - fix segfault cases related to hostname()
  - add debug isis xxx command

This patch has been approved by Paul Jakma.
diff --git a/SERVICES b/SERVICES
index 41d4b94..d74098f 100644
--- a/SERVICES
+++ b/SERVICES
@@ -15,3 +15,4 @@
 ospfd		2604/tcp
 bgpd		2605/tcp
 ospf6d		2606/tcp
+isisd		2607/tcp