Fixed SMB2 rename operations from Vista clients

Fixed SMB2 rename operations from Vista clients

We needed a flag in bufinfo to mark packets as SMB2, as it seems that
SMB2 uses a different format for the RenameInformation buffer than SMB
does

Also handle the fact that SMB2 clients give the full path to the
target file in the rename, not a relative path
(This used to be commit 52d7972d95ddc19d22a4187b4d4428a6c3ed32d5)