Quagga: Fix code to use srandom/random

Quagga was using a mix of srand/rand and srandom/random.
Consolidate to use srandom/random which are the POSIX
versions of random number generators

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/isisd/isis_main.c b/isisd/isis_main.c
index 60ecb75..e1af71f 100644
--- a/isisd/isis_main.c
+++ b/isisd/isis_main.c
@@ -320,7 +320,7 @@
   master = thread_master_create ();
 
   /* random seed from time */
-  srand (time (NULL));
+  srandom (time (NULL));
 
   /*
    *  initializations