don't request file position from remote server in seek implementation
don't request file position from remote server in seek implementation

According to https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/d4bc551b-7aaf-4b4f-ba0e-3a75e7c528f0#Appendix_A_119:

  Both the query and set FilePositionInformation operations are processed on the local client; therefore, these operations are not transmitted across the wire.  The fact that these operations are processed on the client instead of the server is intended to be transparent to the client's usage of these operations.

So, don't request file position from remote server.

Fixes #4

hirochachacha/go-smb2