Fix %files section to not claim ownership of bindir and mandir

Addresses: #50 basho/riak_cs#554

The %files section had to general a case for both (s)bindir
and mandir, specifying the actual directory rather than the
contents of the directory.  This change simply changes those
two lines to be the `<dir>/*` style as recommended in the
[fedora package maintainers documentation](http://fedoraproject.org/wiki/How_to_create_an_RPM_package#.25files_section)
Merge pull request #54 from basho/jem-rpm-files-directive

Fix %files section to not claim ownership of bindir and mandir