Ensure http_connect is mocked out in tests

Otherwise this test will try to connect to several addresses that aren't
mapped. On Linux the entier 127.0.0.* block is mapped to localhost, so this
often isn't noticed, but on OS X only 127.0.0.1 is mapped by default.

Change-Id: I44034d5006ff25e052afdb6599ab5838e4c5ae5b
Merge "Ensure http_connect is mocked out in tests"