Malformed dictionary was causing SyntaxError in Python 2.6

A malformed dictionary was causing _SyntaxError_ in Python 2.6 and older.

````
File "connectionmanager.py", line 8
  listNode = ProtocolTreeNode("list", {"name", "default"}, privacyNodes)
                                             ^
SyntaxError: invalid syntax
````

__FIX__: Replaced ````,```` for ````:````.