[werror] Fix mismatched tags (struct vs. class) inconsistence

Signed-off-by: Thorsten Behrens <tbehrens@suse.com>
Hmmmm. But that would prevent any typechecking (and require a chunk of ugly reinterpret_casts). To me, it would feel more idiomatic to use forward-declared struct CephContext, struct ceph_mount_info, and violate the 'struct is always dumb data container' rule this time.

That also appears to be the least invasive change ;)