Replace fmt.Errorf() with errors.Errorf() in the cli

Signed-off-by: Daniel Nephin <dnephin@docker.com>

command/formatter/reflect.go

@@ -2,9 +2,10 @@ package formatter
 
 import (
 	"encoding/json"
-	"fmt"
 	"reflect"
 	"unicode"
+
+	"github.com/pkg/errors"
 )
 
 func marshalJSON(x interface{}) ([]byte, error) {
@@ -19,14 +20,14 @@ func marshalJSON(x interface{}) ([]byte, error) {
 func marshalMap(x interface{}) (map[string]interface{}, error) {
 	val := reflect.ValueOf(x)
 	if val.Kind() != reflect.Ptr {
-		return nil, fmt.Errorf("expected a pointer to a struct, got %v", val.Kind())
+		return nil, errors.Errorf("expected a pointer to a struct, got %v", val.Kind())
 	}
 	if val.IsNil() {
-		return nil, fmt.Errorf("expected a pointer to a struct, got nil pointer")
+		return nil, errors.Errorf("expected a pointer to a struct, got nil pointer")
 	}
 	valElem := val.Elem()
 	if valElem.Kind() != reflect.Struct {
-		return nil, fmt.Errorf("expected a pointer to a struct, got a pointer to %v", valElem.Kind())
+		return nil, errors.Errorf("expected a pointer to a struct, got a pointer to %v", valElem.Kind())
 	}
 	typ := val.Type()
 	m := make(map[string]interface{})
@@ -48,7 +49,7 @@ var unmarshallableNames = map[string]struct{}{"FullHeader": {}}
 // It returns ("", nil, nil) for valid but non-marshallable parameter. (e.g. "unexportedFunc()")
 func marshalForMethod(typ reflect.Method, val reflect.Value) (string, interface{}, error) {
 	if val.Kind() != reflect.Func {
-		return "", nil, fmt.Errorf("expected func, got %v", val.Kind())
+		return "", nil, errors.Errorf("expected func, got %v", val.Kind())
 	}
 	name, numIn, numOut := typ.Name, val.Type().NumIn(), val.Type().NumOut()
 	_, blackListed := unmarshallableNames[name]