s3: Move up declaration of params struct and related function.

s3: Move up declaration of params struct and related function.

    We need the parameters earlier in the code so we move up
    the declaration of the params struct. Since reading the
    parameters is closely related the definition of the function
    smbacl4_get_vfs_params has also been moved up.

Reviewed-By: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>