Remove proto_tree from capture_file and PacketWinData, since they

Remove proto_tree from capture_file and PacketWinData, since they
already contain a pointer to an epan_dissect_t, which contains
the proto_tree.

Routines calling epan_dissect_new() do not create their own
proto_tree via proto_tree_create_root(); instead, they pass a boolean
to epan_dissect_new() telling it whether it should create the root
proto_tree.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@4343 f5534014-38df-0310-8fa8-9805f1628bb7