Remove log that is always generated for annotation fields. (#652)

 * (M) ytypes/container.go
  - Since schemas that are generated with annotations will always
    generate the log that says that unmarshal into them is unsupported
    the log message produced is extremely low value to a user. To this
    end - just remove it.

ytypes/container.go

@@ -19,7 +19,6 @@ import (
 	"reflect"
 	"strings"
 
-	log "github.com/golang/glog"
 	"github.com/kylelemons/godebug/pretty"
 	"github.com/openconfig/goyang/pkg/yang"
 	"github.com/openconfig/ygot/util"
@@ -158,7 +157,6 @@ func unmarshalStruct(schema *yang.Entry, parent interface{}, jsonTree map[string
 		// Skip annotation fields since they do not have a schema.
 		// TODO(robjs): Implement unmarshalling annotations.
 		if util.IsYgotAnnotation(ft) {
-			log.Infof("ignoring annotation field %s during unmarshalling, unsupported", ft.Name)
 			// We need to find the paths that we should have unmarshalled here to avoid
 			// throwing errors to users whilst there is a TODO above.
 			paths, err := pathTagFromField(ft)