fixed issue with server saving empty node list when caching to disk for first run

kademlia/__init__.py

@@ -3,5 +3,5 @@ Kademlia is a Python implementation of the Kademlia protocol for U{Twisted <http
 
 @author: Brian Muller U{bamuller@gmail.com}
 """
-version_info = (0, 2)
+version_info = (0, 3)
 version = '.'.join(map(str, version_info))

kademlia/network.py

@@ -176,6 +176,9 @@ class Server(object):
                  'alpha': self.alpha,
                  'id': self.node.id,
                  'neighbors': self.bootstrappableNeighbors() }
+        if len(data['neighbors']) == 0:
+            self.log.warning("No known neighbors, so not writing to cache.")
+            return
         with open(fname, 'w') as f:
             pickle.dump(data, f)