CMake - add -ldl for building on Arch (and alike)

Signed-off-by: Adam C. Emerson <aemerson@linuxbox.com>

Conflicts:
	src/CMakeLists.txt
init-ceph - ceph-disk is in SBINDIR
Port Dan's python patch

(Or part of it.)

Signed-off-by: Adam C. Emerson <aemerson@linuxbox.com>