Defined the request argument of ioctl() as unsigned long

Defined the request argument of ioctl() as unsigned long

On linux the request argument of ioctl() is defined as an unsigned long,
but the fuse protocol squashes it into a signed int. As a consequence
the value received by ntfs-3g may appear as negative and different from
the value defined by the corresponding macro.
So define the request argument as unsigned long in ntfs-3g. It has
however to be fed as unsigned from fuse until the fuse protocol is
updated.