_query_dns doesnt use all nameservers in the list

[thesyst]

If you list several servers in 'nameservers' argument of any function (for example 'check_domains') and the first server on the list won't answer during timeout, 'dns.exception.Timeout' will be raised. No other servers on the list will have a chance to process this query, only the first one will.

Example (first server was made incorrect intentionally):

result = checkdmarc.get_spf_record('google.com', nameservers=['8.8.8.81', '8.8.8.8'])