bugfix: not save ExecIds to meta.json file

Signed-off-by: Michael Wan <[email protected]>

Author: HusterWan

daemon/mgr/container_types.go

@@ -192,7 +192,7 @@ type Container struct {
 	Driver string `json:"Driver,omitempty"`
 
 	// exec ids
-	ExecIds []string `json:"ExecIDs,omitempty"`
+	ExecIds []string `json:"-"`
 
 	// Snapshotter, GraphDriver is same, keep both
 	// just for compatibility