Merge pull request #2529 from dongluochen/update_swarm_v1.2.6-rc2

update swarm v1.2.6-rc2

library/swarm

@@ -5,8 +5,8 @@ Maintainers: Alexandre Beslic <[email protected]> (@abronan),
              Victor Vieux <[email protected]> (@vieux)
 GitRepo: https://github.com/docker/swarm-library-image.git
 
-Tags: 1.2.6-rc1
-GitCommit: e33419371f34db2ebbe9a67271de30620e01e88e
+Tags: 1.2.6-rc2
+GitCommit: e8268874ec7b6af365cf6a90e02ad3af89c82830
 
 Tags: 1.2.5, latest
 GitCommit: 67e6cf4171fcabd2e3b8b809105e7dfb15114ce1