Remove `ContainerWait` from docker client

`ContainerWait` is not being used anywhere at this point, there are
plans to use it as a replacement for gitlab-runner `waitForContainer`
func over at  https://gitlab.com/gitlab-org/gitlab-runner/issues/3918,
but in the mean time it should be removed since it's dead code.

helpers/docker/client.go

@@ -17,7 +17,6 @@ type Client interface {
 
 	ContainerCreate(ctx context.Context, config *container.Config, hostConfig *container.HostConfig, networkingConfig *network.NetworkingConfig, containerName string) (container.ContainerCreateCreatedBody, error)
 	ContainerStart(ctx context.Context, containerID string, options types.ContainerStartOptions) error
-	ContainerWait(ctx context.Context, containerID string) (int64, error)
 	ContainerKill(ctx context.Context, containerID, signal string) error
 	ContainerInspect(ctx context.Context, containerID string) (types.ContainerJSON, error)
 	ContainerAttach(ctx context.Context, container string, options types.ContainerAttachOptions) (types.HijackedResponse, error)

helpers/docker/mock_Client.go

@@ -200,27 +200,6 @@ func (_m *MockClient) ContainerStart(ctx context.Context, containerID string, op
 	return r0
 }
 
-// ContainerWait provides a mock function with given fields: ctx, containerID
-func (_m *MockClient) ContainerWait(ctx context.Context, containerID string) (int64, error) {
-	ret := _m.Called(ctx, containerID)
-
-	var r0 int64
-	if rf, ok := ret.Get(0).(func(context.Context, string) int64); ok {
-		r0 = rf(ctx, containerID)
-	} else {
-		r0 = ret.Get(0).(int64)
-	}
-
-	var r1 error
-	if rf, ok := ret.Get(1).(func(context.Context, string) error); ok {
-		r1 = rf(ctx, containerID)
-	} else {
-		r1 = ret.Error(1)
-	}
-
-	return r0, r1
-}
-
 // ImageImportBlocking provides a mock function with given fields: ctx, source, ref, options
 func (_m *MockClient) ImageImportBlocking(ctx context.Context, source types.ImageImportSource, ref string, options types.ImageImportOptions) error {
 	ret := _m.Called(ctx, source, ref, options)

helpers/docker/official_docker_client.go

@@ -86,12 +86,6 @@ func (c *officialDockerClient) ContainerStart(ctx context.Context, containerID s
 	return wrapError("ContainerCreate", err, started)
 }
 
-func (c *officialDockerClient) ContainerWait(ctx context.Context, containerID string) (int64, error) {
-	started := time.Now()
-	result, err := c.client.ContainerWait(ctx, containerID)
-	return result, wrapError("ContainerWait", err, started)
-}
-
 func (c *officialDockerClient) ContainerKill(ctx context.Context, containerID string, signal string) error {
 	started := time.Now()
 	err := c.client.ContainerKill(ctx, containerID, signal)