Revendor github.com/Microsoft/hcsshim

1. Revendors github.com/Microsoft/hcsshim to the latest known good commit.
This includes numerous bug fixes and improvements.

2. Vendors indirect dependency on go.opencensus.io since hcsshim now uses trace
correlation.

Signed-off-by: Justin Terry (VM) <juterry@microsoft.com>

vendor/github.com/Microsoft/hcsshim/internal/schema2/statistics.go

@@ -15,7 +15,6 @@ import (
 
 //  Runtime statistics for a container
 type Statistics struct {
-
 	Timestamp time.Time `json:"Timestamp,omitempty"`
 
 	ContainerStartTime time.Time `json:"ContainerStartTime,omitempty"`