[test/integration] Small daemon refactoring and add swarm init/join helpers

[vdemeester]

🦁

Signed-off-by: Vincent Demeester vincent@sbr.pm

[vdemeester]

hum I broke something 🤔 (should be fixed now)

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@ea579a6). Click here to learn what that means.
The diff coverage is n/a.

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[thaJeztah]

Janky is failing on a flaky test; https://jenkins.dockerproject.org/job/Docker-PRs/48971/console, which is tracked through #32673

16:29:12 ----------------------------------------------------------------------
16:29:12 FAIL: docker_api_swarm_test.go:297: DockerSwarmSuite.TestAPISwarmLeaderElection
16:29:12 
16:29:12 [d478405b8f18b] waiting for daemon to start
16:29:12 [d478405b8f18b] daemon started
16:29:12 
16:29:12 [d5b688c6ab843] waiting for daemon to start
16:29:12 [d5b688c6ab843] daemon started
16:29:12 
16:29:12 [deb10f5554730] waiting for daemon to start
16:29:12 [deb10f5554730] daemon started
16:29:12 
16:29:12 [d478405b8f18b] exiting daemon
16:29:12 assertion failed: error is not nil: Error response from daemon: rpc error: code = DeadlineExceeded desc = context deadline exceeded
16:29:12 [d5b688c6ab843] exiting daemon
16:29:12 [deb10f5554730] exiting daemon
16:29:36 

Windows failure (https://jenkins.dockerproject.org/job/Docker-PRs-WoW-RS1/20409/console) is also flaky #33301

16:10:27 ----------------------------------------------------------------------
16:10:27 FAIL: docker_api_logs_test.go:23: DockerSuite.TestLogsAPIWithStdout
16:10:27 
16:10:27 docker_api_logs_test.go:55:
16:10:27     c.Fatal("timeout waiting for logs to exit")
16:10:27 ... Error: timeout waiting for logs to exit
16:10:27 

[cpuguy83]

LGTM

[anusha-ragunathan]

LGTM