Re-think integration vendoring

- remove docker/docker from  Traefik vendor (unused)
- use `ignore` for all Traefik vendor in integration glide.
- defined only integration specific version of the dependencies.

integration/vendor/github.com/xeipuuv/gojsonschema/errors.go

@@ -1,10 +1,20 @@
 package gojsonschema
 
 import (
-	"fmt"
-	"strings"
+	"bytes"
+	"sync"
+	"text/template"
 )
 
+var errorTemplates errorTemplate = errorTemplate{template.New("errors-new"), sync.RWMutex{}}
+
+// template.Template is not thread-safe for writing, so some locking is done
+// sync.RWMutex is used for efficiently locking when new templates are created
+type errorTemplate struct {
+	*template.Template
+	sync.RWMutex
+}
+
 type (
 	// RequiredError. ErrorDetails: property string
 	RequiredError struct {
@@ -227,16 +237,47 @@ func newError(err ResultError, context *jsonContext, value interface{}, locale l
 	err.SetValue(value)
 	err.SetDetails(details)
 	details["field"] = err.Field()
+
+	if _, exists := details["context"]; !exists && context != nil {
+		details["context"] = context.String()
+	}
+
 	err.SetDescription(formatErrorDescription(d, details))
 }
 
-// formatErrorDescription takes a string in this format: %field% is required
-// and converts it to a string with replacements. The fields come from
-// the ErrorDetails struct and vary for each type of error.
+// formatErrorDescription takes a string in the default text/template
+// format and converts it to a string with replacements. The fields come
+// from the ErrorDetails struct and vary for each type of error.
 func formatErrorDescription(s string, details ErrorDetails) string {
-	for name, val := range details {
-		s = strings.Replace(s, "%"+strings.ToLower(name)+"%", fmt.Sprintf("%v", val), -1)
+
+	var tpl *template.Template
+	var descrAsBuffer bytes.Buffer
+	var err error
+
+	errorTemplates.RLock()
+	tpl = errorTemplates.Lookup(s)
+	errorTemplates.RUnlock()
+
+	if tpl == nil {
+		errorTemplates.Lock()
+		tpl = errorTemplates.New(s)
+
+		if ErrorTemplateFuncs != nil {
+			tpl.Funcs(ErrorTemplateFuncs)
+		}
+
+		tpl, err = tpl.Parse(s)
+		errorTemplates.Unlock()
+
+		if err != nil {
+			return err.Error()
+		}
 	}
 
-	return s
+	err = tpl.Execute(&descrAsBuffer, details)
+	if err != nil {
+		return err.Error()
+	}
+
+	return descrAsBuffer.String()
 }