bug: test TLS always fail in i386 env

[mckaygerhard]

test TLS always fail in i386 env using golang 1.8:

seems the httpdown facebook need network connection to work that test?

--- PASS: TestTLS (0.10s)
FAIL
FAIL	github.com/facebookgo/httpdown	0.118s
?   	github.com/facebookgo/httpdown/httpdown_example	[no test files]
dh_auto_test: go test -v -p 10 github.com/facebookgo/httpdown github.com/facebookgo/httpdown/httpdown_example returned exit code 1