[19.03] vendor: update buildkit for 19.03

[tonistiigi]

Brings in [docker-19.03] docker 19.03 / v0.6.2 cherry picks moby/buildkit#1178. Which cherry-picks the following changes into the BuildKit version used;

• Fix socket handling moby/buildkit#1144 Fix socket handling
• session: release forwarded ssh socket connection per connection moby/buildkit#1150 session: release forwarded ssh socket connection per connection
• llbsolver: fix error on multiple cache importers moby/buildkit#1156 llbsolver: fix error on multiple cache importers
• http: Handle missing but unambiguous ETags in response moby/buildkit#1159 http: Handle missing but unambiguous ETags in response
• solver: fix pipe signaling on incoming updates moby/buildkit#1166 solver: fix pipe signaling on incoming updates
• vendor: update go-runc to e029b79d moby/buildkit#1168 vendor: update go-runc to e029b79d8cda8374981c64eba71f28ec38e5526f
  • fixes User namespace remapping breaks BuildKit-powered builds (19.03.2) moby/moby#39866 User namespace remapping breaks BuildKit-powered builds (19.03.2)

[andrewhsu]

I'm seeing failure but I think it is unrelated:

 --- FAIL: TestServiceWithDefaultAddressPoolInit (1.45s)
     service_test.go:398: Creating a new daemon at: /go/src/github.com/docker/docker/bundles/test-integration/1/TestServiceWithDefaultAddressPoolInit
     daemon.go:321: [dd1e75d7749c9] waiting for daemon to start
     daemon.go:339: [dd1e75d7749c9] daemon started
     service_test.go:423: TestServiceWithDefaultAddressPoolInit: NetworkInspect: {Name:saanvisthiraTestServiceWithDefaultAddressPoolInit ID:zgtqppmcdlfi5op5tw5gdbxu8 Created:2019-09-21 01:06:10.441820056 +0000 UTC Scope:swarm Driver:overlay EnableIPv6:false IPAM:{Driver:default Options:map[] Config:[{Subnet:20.20.1.0/24 IPRange: Gateway:20.20.1.1 AuxAddress:map[]}]} Internal:false Attachable:false Ingress:false ConfigFrom:{Network:} ConfigOnly:false Containers:map[] Options:map[com.docker.network.driver.overlay.vxlanid_list:4097] Labels:map[] Peers:[] Services:map[]}
     service_test.go:425: assertion failed: 20.20.1.0/24 (out.IPAM.Config[0].Subnet string) != 20.20.0.0/24 (string)

[andrewhsu]

@tonistiigi can you rebase this? reverted the swarmkit changes that was causing TestServiceWithDefaultAddressPoolInit failures

[andrewhsu]

LGTM

amd64 tests green