Improve ConsulService.resolve()

[vsudilov]

From @vsudilov on July 22, 2015 14:54

The current implementation that heavily relies on dnspython is opaque and exceedingly difficult to test; This should be improved.

Copied from original issue: adsabs/adsws#74

[vsudilov]

https://github.com/pstiasny/requests-srv
drop-in replacement for requests that will resolve SRV records:

In [38]: requests.get('http://_montysolr._tcp.service.consul/solr')                                                                                                               
Out[38]: <Response [200]> 

This would be an improvement to the custom DNS code here.

[vsudilov]

One problem with this approach is that specifying tags is not supported in the SRV RFC afaik