fuse: update to newer FUSE_USE_VERSION

fuse: update to newer FUSE_USE_VERSION

The build was failing for me against fuse-devel v3.9.1. The prototype
for fuse_ll_ioctl was wrong, as it was expecting the old-style one with
signed int args.

In newer libfuse versions, the prototype varies based on
FUSE_USE_VERSION. Update to a newer FUSE_USE_VERSION value to ensure
that we use the newer ioctl prototype. This also means that we need to
handle a new prototype for fuse_session_loop_mt as well.

While we're in here, move the definition of FUSE_USE_VERSION to
ceph_fuse.h so we have the definition in one place. This does mean we
need to reorganize the includes in a few places.

Fixes: https://tracker.ceph.com/issues/45866
Signed-off-by: Jeff Layton <jlayton@redhat.com>