smb3: request handle caching when caching directories

This client was only requesting READ caching, not READ and HANDLE caching
in the LeaseState on the open requests we send for directories.  To
delay closing a handle (e.g. for caching directory contents) we should
be requesting HANDLE as well as READ (as we already do for deferred
close of files).   See MS-SMB2 3.3.1.4 e.g.

Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>