[PATCH] Make sure we return an iterable of chan.get is we use it that way

Make sure chan.get('BridgedChannel') returns an iterable if used in a construct which expects one.

The situation where the current code generates an exception is that when 'BridgedChannel' is not key in the status. A 'None' would be returned, which is not iterable. By returning an empty string, we prevent the exception.

Patch:
=== modified file 'asterisk_click2dial/asterisk_click2dial.py'
--- asterisk_click2dial/asterisk_click2dial.py 2013-04-15 06:46:08 +0000
+++ asterisk_click2dial/asterisk_click2dial.py 2013-04-30 11:48:57 +0000
@@ -299,7 +299,7 @@
                     _logger.debug("Found a matching Event in 'Ring' state")
                     calling_party_number = chan.get('CallerIDNum')
                     break
- if chan.get('ChannelState') == '6' and sip_account in chan.get('BridgedChannel'): # 6 = Up
+ if chan.get('ChannelState') == '6' and sip_account in chan.get('BridgedChannel',''): # 6 = Up
                     _logger.debug("Found a matching Event in 'Up' state")
                     calling_party_number = chan.get('CallerIDNum')
                     break