Ehm.. corretto un altro bug

diff --git a/RaiTV/ChannelLoader.py b/RaiTV/ChannelLoader.py
index be4a794..b7d1c75 100644
--- a/RaiTV/ChannelLoader.py
+++ b/RaiTV/ChannelLoader.py
@@ -39,6 +39,7 @@ class ChannelList():
                               None,
                               { 'User-Agent': self.UA })
         r = urllib2.urlopen(req)
+        self.channels.clear()
         self.parseChannels(r.read())

     def parseChannels(self, xmlfile):