[18.09 backport] Switch to go 1.11#2836

dperny merged 2 commits intomoby:bump_v18.09moby/swarmkit:bump_v18.09from

thaJeztah:18.09_backport_bump_golang_1.11thaJeztah/swarmkit:18.09_backport_bump_golang_1.11Copy head branch name to clipboard