aiodns tests fail because "example.com" gives different IP address on each query

[korn3r]

Hi. Title pretty much describes issue. Couldnt build latest (0.21) uvloop rpm because dns test failed because of IP addresses not match. example.com seems ot be behind CDN, thus there are a lot of IP addresses. Workaround for me was just add "example.com" entry into hosts, but i decided i should probably create issue on github too.