ceph: Fix warnings

Just scrubbing some warnings so I can see real problem ones in the build
noise. For 32bit we need to coax gcc politely into believing we really
honestly intend to the casts. Using (u64)(unsigned long) means we cast from
a pointer to a type of the right size and then extend it. This stops the
warning spew.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Sage Weil <sage@newdream.net>