Port dialyzer warning fixes from #528.
Fix some more dialyzer warnings.

riak_core_console:

* del_source/2 and add_grant/3 always returns 'ok'.
* Make sure that parse_cidr/1 and parse_options() match up with the
  types expected from riak_core_security.

riak_core_security:

* add_grant/3 and add_revoke/3 accept 'any' as a bucket name.
* add_source/4 uses Source as an atom.