Install public key in standard place.

--- a/BitTorrent/NewVersion.py
+++ b/BitTorrent/NewVersion.py
@@ -163,7 +163,7 @@ class Updater(object):
             self.threadwrap(self.errorfunc, WARNING, '\n'.join(terrors))
 
         if torrentfile and signature:
-            public_key_file = open(os.path.join(doc_root, 'public.key'), 'rb')
+            public_key_file = open('/etc/pki/bittorrent/public.key', 'rb')
             public_key = pickle.load(public_key_file)
             h = sha(torrentfile).digest()
             if public_key.verify(h, signature):