Merge pull request docker-archive#2435 from nishanttotla/bump-1.2.4

Bump version to 1.2.4

swarm 1.2.3 docs fixes

Merge pull request docker-archive#2426 from nishanttotla/bump-v1.2.4-rc2

Bump version to v1.2.4-rc2

generated tag from history

Merge pull request docker-archive#2350 from nishanttotla/bump-v1.2.4-rc1

Bump version to 1.2.4-rc1

generated tag from history

Merge pull request docker-archive#2257 from allencloud/fix-unit-test-…

…command-in-CONTRIBUTION

fix unit test command in CONTRIBUTION.md

Merge pull request docker-archive#2282 from nishanttotla/bump-v1.2.3-rc1

Bump version to v1.2.3-rc1

Merge pull request docker-archive#2215 from joelhandwell/patch-1

Krane project has been closed in favor of Machine

Merge pull request docker-archive#2211 from nishanttotla/bump-1.2.2-rc1

Bump version to 1.2.2-rc1