Debug e2e ci errors

Created by: chrismwendt

CI errored out before running e2e tests earlier today:

https://buildkite.com/sourcegraph/sourcegraph/builds/28952#dea33fa5-e581-4cd9-a2d4-1084aee65ec8

+ timeout 30s bash -c 'until curl --output /dev/null --silent --head --fail http://localhost:7080; do
--
  | echo Waiting 5s for http://localhost:7080...
  | sleep 5
  | done'
  | + socat tcp-listen:7080,reuseaddr,fork 'system:docker exec -i 7debb79dd4b5edd39e133551fb9c0c42c8d0e68ff77884d8be9164e6b90c8e5c socat stdio '\''tcp:localhost:7080'\'''
  | 2019/03/06 01:46:56 socat[43] E connect(5, AF=2 127.0.0.1:7080, 16): Connection refused
  | 2019/03/06 01:46:56 socat[10745] E waitpid(): child 10751 exited with status 1
  | Waiting 5s for http://localhost:7080...
  | Waiting 5s for http://localhost:7080...
  | Waiting 5s for http://localhost:7080...
  | Waiting 5s for http://localhost:7080...
  | Waiting 5s for http://localhost:7080...
  | Waiting 5s for http://localhost:7080...
  | ++ jobs -p
  | + kill 10745
  | ./dev/ci/e2e.sh: line 1: kill: (10745) - No such process

This PR adds output of docker inspect and docker logs to aid debugging.