integration-cli: add more debugging for TestSwarmClusterRotateUnlockKey
integration-cli: add more debugging for TestSwarmClusterRotateUnlockKey

This test was updated in b79adac339173bf8bb6de6d0a061a97973c4b62b, but is still flaky;

```
20:24:13  FAIL: docker_cli_swarm_test.go:1333: DockerSwarmSuite.TestSwarmClusterRotateUnlockKey
20:24:13
20:24:13  Creating a new daemon at: /go/src/github.com/docker/docker/bundles/test-integration/3/DockerSwarmSuite.TestSwarmClusterRotateUnlockKey
20:24:13  [d6f95e679cb65] waiting for daemon to start
20:24:13  [d6f95e679cb65] waiting for daemon to start
20:24:13  [d6f95e679cb65] daemon started
20:24:13
20:24:13  Creating a new daemon at: /go/src/github.com/docker/docker/bundles/test-integration/3/DockerSwarmSuite.TestSwarmClusterRotateUnlockKey
20:24:13  [d204a02ba4780] waiting for daemon to start
20:24:13  [d204a02ba4780] waiting for daemon to start
20:24:13  [d204a02ba4780] daemon started
20:24:13
20:24:13  [d204a02ba4780] joining swarm manager [d6f95e679cb65]@0.0.0.0:2477, swarm listen addr 0.0.0.0:2478
20:24:13  Creating a new daemon at: /go/src/github.com/docker/docker/bundles/test-integration/3/DockerSwarmSuite.TestSwarmClusterRotateUnlockKey
20:24:13  [d873d6a842829] waiting for daemon to start
20:24:13  [d873d6a842829] waiting for daemon to start
20:24:13  [d873d6a842829] daemon started
20:24:13
20:24:13  [d873d6a842829] joining swarm manager [d6f95e679cb65]@0.0.0.0:2477, swarm listen addr 0.0.0.0:2479
20:24:13  [d204a02ba4780] Stopping daemon
20:24:13  [d204a02ba4780] exiting daemon
20:24:13  [d204a02ba4780] Daemon stopped
20:24:13  [d204a02ba4780] waiting for daemon to start
20:24:13  [d204a02ba4780] waiting for daemon to start
20:24:13  [d204a02ba4780] daemon started
20:24:13
20:24:13  [d873d6a842829] Stopping daemon
20:24:13  [d873d6a842829] exiting daemon
20:24:13  [d873d6a842829] Daemon stopped
20:24:13  [d873d6a842829] waiting for daemon to start
20:24:13  [d873d6a842829] waiting for daemon to start
20:24:13  [d873d6a842829] daemon started
20:24:13
20:24:13  docker_cli_swarm_test.go:1413:
20:24:13      c.Assert(err, checker.IsNil, check.Commentf("%s", outs))
20:24:13  ... value *exec.ExitError = &exec.ExitError{ProcessState:(*os.ProcessState)(0xc000934240), Stderr:[]uint8(nil)} ("exit status 1")
20:24:13  ... Error response from daemon: rpc error: code = Unknown desc = The swarm does not have a leader. It's possible that too few managers are online. Make sure more than half of the managers are online.
20:24:13
20:24:13
20:24:13  [d6f95e679cb65] Stopping daemon
20:24:13  [d6f95e679cb65] exiting daemon
20:24:13  [d6f95e679cb65] Daemon stopped
20:24:13  [d204a02ba4780] Stopping daemon
20:24:13  [d204a02ba4780] exiting daemon
20:24:13  [d204a02ba4780] Daemon stopped
20:24:13  [d873d6a842829] Stopping daemon
20:24:13  [d873d6a842829] exiting daemon
20:24:13  [d873d6a842829] Daemon stopped
```

The interesting bit there is that the retry loop should have a 3 second sleep before retrying,
but looking at the failure above, the test started (and failed) within a second, which means that
a different error / output was returned.

This patch adds some additional debugging to that test to see if we can catch the reason
this test is still flaky.

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

nawawi/docker,docker/docker,Ramzec/docker,vdemeester/docker,mahak/docker,Ramzec/docker,djs55/docker,paralin/docker,yongtang/docker,jameszhan/docker,SvenDowideit/docker,Mokolea/docker,moul/docker,justincormack/docker,flavio/docker,yosifkit/docker,nalind/docker,konstruktoid/docker-1,trebonian/docker,AkihiroSuda/docker,yongtang/docker,cpuguy83/docker,thaJeztah/docker,estesp/docker,nalind/docker,ibuildthecloud/docker,cpuguy83/docker,pradipd/moby,trebonian/docker,dims/docker,jthelin/docker,trebonian/docker,konstruktoid/docker-1,justincormack/docker,vdemeester/docker,cpuguy83/docker,moul/docker,jimjag/docker,yosifkit/docker,vdemeester/docker,yosifkit/docker,Mokolea/docker,dims/docker,moby/moby,jameszhan/docker,paralin/docker,jthelin/docker,docker/docker,Mokolea/docker,nawawi/docker,jimjag/docker,SvenDowideit/docker,trebonian/docker,ibuildthecloud/docker,moby/moby,kojiromike/docker,AkihiroSuda/docker,kojiromike/docker,jvanz/docker,AkihiroSuda/docker,estesp/docker,Ramzec/docker,bearstech/moby,nalind/docker,jimjag/docker,bearstech/moby,cpuguy83/docker,estesp/docker,mahak/docker,flavio/docker,gnailuy/docker,jvanz/docker,mahak/docker,nawawi/docker,konstruktoid/docker-upstream,djs55/docker,thaJeztah/docker,ibuildthecloud/docker,ibuildthecloud/docker,paralin/docker,yosifkit/docker,kojiromike/docker,thaJeztah/docker,konstruktoid/docker-upstream,ibuildthecloud/docker,gnailuy/docker,SvenDowideit/docker,gnailuy/docker,nalind/docker,gnailuy/docker,docker/docker,konstruktoid/docker-1,thaJeztah/docker,moby/moby,dims/docker,pradipd/moby,jvanz/docker,jimjag/docker,konstruktoid/docker-upstream,paralin/docker,flavio/docker,moby/moby,mahak/docker,moul/docker,Mokolea/docker,konstruktoid/docker-upstream,flavio/docker,AkihiroSuda/docker,djs55/docker,bearstech/moby,Ramzec/docker,jameszhan/docker,pradipd/moby,moul/docker,bearstech/moby,justincormack/docker,nawawi/docker,yongtang/docker