cifs: Use CREATE_OPTION_EXCLUSIVE when doing SMB1 rmdir on NT server

Windows NT servers just set the DELETE_PENDING flag when executing the SMB1
SMB_COM_DELETE_DIRECTORY command. This is opposite of the SMB_COM_DELETE
command (can be used only on files) which completely removes the file and
not just transition it into DELETE_PENDING state.

This means that the SMB1 rmdir against Windows NT servers has same issues
as SMB2+ rmdir and silly rename needs to be used. As in SMB2+ rmdir, use
the CREATE_OPTION_EXCLUSIVE logic for issuing SMB1 rmdir when communicating
with NT-based SMB1 server.

With this change Linux rmdir() syscall called on SMB1 mounts from Windows
NT servers cause that on success the path would not exist anymore and new
file or directory with that path can be created.

Signed-off-by: Pali Rohár <pali@kernel.org>