TestRespondToEcho is logging a panic

[daenney]

As part of #350 we discovered that during a test a panic gets logged, even though the test itself succeeds.

=== RUN   TestRespondToEcho
time="2021-05-19T08:55:31Z" level=info msg="Incoming request" req.id=smW335jjZJSf req.method=POST req.path=/admin/configureClient
time="2021-05-19T08:55:31Z" level=warning msg="Device ID is not set which will result in E2E encryption/decryption not working"
time="2021-05-19T08:55:31Z" level=error msg="Failed to load next_batch token" error="sql: no rows in result set" user_id="@link:hyrule"
time="2021-05-19T08:55:31Z" level=info msg="Created new client" auto_join_rooms=true device_id= since= sync=true user_id="@link:hyrule"
time="2021-05-19T08:55:31Z" level=info msg="Responding (372 bytes)" code=200 req.id=smW335jjZJSf req.method=POST req.path=/admin/configureClient
time="2021-05-19T08:55:31Z" level=info msg="Incoming request" req.id=Bk1hytf2pIFO req.method=POST req.path=/admin/configureService
time="2021-05-19T08:55:31Z" level=info msg="Incoming configure service request" req.id=Bk1hytf2pIFO req.method=POST req.path=/admin/configureService service_id=test_echo_service service_type=echo service_user_id="@link:hyrule"
time="2021-05-19T08:55:31Z" level=info msg="Responding (72 bytes)" code=200 req.id=Bk1hytf2pIFO req.method=POST req.path=/admin/configureService
time="2021-05-19T08:55:31Z" level=error msg="Fatal Sync() error" error="ProcessResponse panicked! since= panic=RoundTrip: Unhandled request: POST /_matrix/client/r0/keys/upload\nHandlers: 2\ngoroutine 12 [running]:\nruntime/debug.Stack(0xc000706e30, 0xba9080, 0xc0001aaa20)\n\t/opt/hostedtoolcache/go/1.16.4/x64/src/runtime/debug/stack.go:24 +0x9f\nmaunium.net/go/mautrix.(*DefaultSyncer).ProcessResponse.func1(0x0, 0x0, 0xc000707d18)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/sync.go:133 +0x76\npanic(0xba9080, 0xc0001aaa20)\n\t/opt/hostedtoolcache/go/1.16.4/x64/src/runtime/panic.go:965 +0x1b9\ngithub.com/matrix-org/go-neb.(*matrixTripper).RoundTrip(0xc0000aaa78, 0xc000112300, 0xc0000aaa78, 0x0, 0x0)\n\t/home/runner/work/go-neb/go-neb/testutil_test.go:43 +0x33f\nnet/http.send(0xc000112300, 0xd96080, 0xc0000aaa78, 0x0, 0x0, 0x0, 0xc0000102c8, 0x1e, 0x1, 0x0)\n\t/opt/hostedtoolcache/go/1.16.4/x64/src/net/http/client.go:251 +0x454\nnet/http.(*Client).send(0xc0001a9890, 0xc000112300, 0x0, 0x0, 0x0, 0xc0000102c8, 0x0, 0x1, 0x419ffb)\n\t/opt/hostedtoolcache/go/1.16.4/x64/src/net/http/client.go:175 +0xff\nnet/http.(*Client).do(0xc0001a9890, 0xc000112300, 0x0, 0x0, 0x0)\n\t/opt/hostedtoolcache/go/1.16.4/x64/src/net/http/client.go:717 +0x45f\nnet/http.(*Client).Do(...)\n\t/opt/hostedtoolcache/go/1.16.4/x64/src/net/http/client.go:585\nmaunium.net/go/mautrix.(*Client).executeCompiledRequest(0xc0004441a0, 0xc000112300, 0x0, 0xee6b2800, 0xb7c920, 0xc0000102b8, 0x0, 0x0, 0x0, 0x0, ...)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/client.go:393 +0xe7\nmaunium.net/go/mautrix.(*Client).MakeFullRequest(0xc0004441a0, 0xcb0dfd, 0x4, 0xc000784c00, 0x2f, 0x0, 0xb8d6e0, 0xc00045b6f0, 0x0, 0x0, ...)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/client.go:360 +0x1e5\nmaunium.net/go/mautrix.(*Client).MakeRequest(...)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/client.go:284\nmaunium.net/go/mautrix.(*Client).UploadKeys(0xc0004441a0, 0xc00045b6f0, 0x1a, 0xc00045b700, 0x1)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/client.go:1184 +0x258\nmaunium.net/go/mautrix/crypto.(*OlmMachine).ShareKeys(0xc00048c000, 0x0, 0x4e, 0xc00045a9d0)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/crypto/machine.go:421 +0x1a5\nmaunium.net/go/mautrix/crypto.(*OlmMachine).ProcessSyncResponse(0xc00048c000, 0xc00046c4d0, 0x0, 0x0, 0x767d18)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/crypto/machine.go:180 +0x305\ngithub.com/matrix-org/go-neb/clients.(*BotClient).syncCallback(0xc0001a5220, 0xc00046c4d0, 0x0, 0x0, 0xcf5f01)\n\t/home/runner/work/go-neb/go-neb/clients/bot_client.go:113 +0x75\nmaunium.net/go/mautrix.(*DefaultSyncer).ProcessResponse(0xc000296e60, 0xc00046c4d0, 0x0, 0x0, 0x0, 0x0)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/sync.go:138 +0x110\nmaunium.net/go/mautrix.(*Client).SyncWithContext(0xc0004441a0, 0xda3a50, 0xc0000a6010, 0x0, 0x0)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/client.go:245 +0x22d\nmaunium.net/go/mautrix.(*Client).Sync(...)\n\t/home/runner/go/pkg/mod/maunium.net/go/[email protected]/client.go:201\ngithub.com/matrix-org/go-neb/clients.(*BotClient).Sync(0xc0001a5220)\n\t/home/runner/work/go-neb/go-neb/clients/bot_client.go:170 +0x185\ncreated by github.com/matrix-org/go-neb/clients.(*Clients).initClient\n\t/home/runner/work/go-neb/go-neb/clients/clients.go:417 +0xd65\n" user_id="@link:hyrule"

We should investigate why this happens and fix it.