tools: ceph-osdomap-tool.cc

Add tool for dumping info from osd omap.

Signed-off-by: Samuel Just <sam.just@inktank.com>
Makefile: put ceph_monstore_tool in bin_DEBUGPROGRAMS

Signed-off-by: Samuel Just <sam.just@inktank.com>
Makefile,gitignore: ceph-monstore-tool, not ceph_monstore_tool

Signed-off-by: Samuel Just <sam.just@inktank.com>