PubSub tests hang with go-ipfs master

[ghost]

Example: https://travis-ci.org/ipfs/go-ipfs-api/jobs/304527816

This seems to have started with the merge of ipfs/kubo#3856.

I changed the t.Log() calls to fmt.Printf() locally, and saw that it's hanging at subscribing..., and Wireshark tells me that the API doesn't bother sending response header until the first message comes in (which I emulated with ipfs pubsub pub test foobar).

=== RUN   TestAdd
--- PASS: TestAdd (0.00s)
=== RUN   TestLocalShell
--- PASS: TestLocalShell (0.00s)
=== RUN   TestCat
--- PASS: TestCat (0.00s)
=== RUN   TestList
--- PASS: TestList (0.00s)
=== RUN   TestFileList
--- PASS: TestFileList (0.00s)
=== RUN   TestPins
--- PASS: TestPins (0.01s)
=== RUN   TestPatch_rmLink
--- PASS: TestPatch_rmLink (0.00s)
=== RUN   TestPatchLink
--- PASS: TestPatchLink (0.00s)
=== RUN   TestResolvePath
--- PASS: TestResolvePath (0.00s)
=== RUN   TestPubSub
subscribing...

[ghost]

Fixed in #63 and ipfs/kubo#4402