[#420] Fixed incorrect parsing of `indices` option when the alias contains `routing` values

If a routing value is set, Elasticsearch returns a key called "index_routing",
which can overwrite the "indices" or "index" value if it comes later in the hash iteration,
since that key also matches the regex "/index|indices/".

Closes #420
[#420] Added unit tests for the `Alias` parsing bug fix

Added tests for karmi/tire@8fae686, replacing tests from mriley/tire@835c4cd.