[WIP] Upgrade to containerd v1.2

[fuweid]

Ⅰ. Describe what this PR did

The containerd has been improved a lot in v1.2, which makes the service
stable than before. Based on this, we need to do the upgrade.

using following commands to update the vendor

govendor fetch github.com/containerd/containerd/...@v1.2.0
govendor fetch github.com/gogo/protobuf/...@v1.0.0
govendor fetch github.com/gogo/googleapis/...@08a7655d27152912db7aaf4f983275eaf8d128ef
govendor fetch google.golang.org/grpc/...@v1.12.0
govendor fetch github.com/golang/protobuf/...@v1.1.0

Basically, both the contaienrd and shim API interfaces are stable so
that we don't need to worry about the remote API calls. However, the
package level interface has been changed a lot. The commit is used to
align with containerd@v1.2.0.

1. events part:
   using exchange event helper instead of raw grpc conn

2. image part:
  a. import:
     new Import interface makes the import easier without Importer.

  b. commit:
     content helper has been upgraded with less arguments for caller.
     and `diff` package separates the Applier and Comparer interfaces.
     The changes can make the code clear in PouchContainer

3. lease:
  containerd client doesn't provide ListLeases interface directly.
  PouchContainer needs to get LeasesService and make the call by itself.

4. container IO:
  remove codes which comes from containerd. The code was used to align
  with containerd v1.2, which can make upgrade work easier. For now, we
  can remove this.

I also use subshell to run the integration::ping_pouchd command so that the error log can show up in CI.

Ⅱ. Does this pull request fix one issue?

NONE

Ⅲ. Why don't you add test cases (unit test/integration test)? (你真的觉得不需要加测试吗？)

no need

Ⅳ. Describe how to verify it

use existing CI testing case

Ⅴ. Special notes for reviews

I separate the change into two commits because the vendor change is too big.
There are somethings need to do after this PR, for example, it is time to remove the ctrd/wrapper_client.go because the grpc has been updated and it can support the defaultMaxStreamsClient

related to containerd/containerd#2862

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@9ed34bb). Click here to learn what that means.
The diff coverage is 42.1%.

@@            Coverage Diff            @@
##             master    #2530   +/-   ##
=========================================
  Coverage          ?   54.87%           
=========================================
  Files             ?      277           
  Lines             ?    18426           
  Branches          ?        0           
=========================================
  Hits              ?    10112           
  Misses            ?     7054           
  Partials          ?     1260

Flag	Coverage Δ
#criv1alpha1test	31.16% <42.1%> (?)
#criv1alpha2test	35.18% <36.84%> (?)
#unittest	26.86% <0%> (?)

Impacted Files	Coverage Δ
pkg/jsonstream/image_progress.go	0% <ø> (ø)
daemon/mgr/image_load.go	0% <0%> (ø)
ctrd/image.go	58.87% <0%> (ø)
ctrd/utils.go	69.01% <0%> (ø)
daemon/mgr/image.go	38.22% <0%> (ø)
ctrd/image_commit.go	0% <0%> (ø)
daemon/mgr/image_utils.go	85.45% <100%> (ø)
daemon/containerio/io.go	70.87% <100%> (ø)
daemon/containerio/cio.go	70% <100%> (ø)
ctrd/snapshot.go	64% <100%> (ø)
... and 3 more

[fuweid]

the first commit is for vendor update and the second one is for code change. hope it can help.

[fuweid]

still investigate the failed cases about load/save functionality. It seems that the containerd export functionality doesn't support the image which has several manifests.

[Ace-Tang]

Hold this pr

[pouchrobot]

ping @fuweid
Conflict happens after merging a previous commit.
Please rebase the branch against master and push it back again. Thanks a lot.

[fuweid]

close it and re-create other one