Vendor containers/storage for better error reporting on dups

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

Closes: #971
Approved by: mheon

vendor/github.com/containers/storage/containers.go

@@ -2,6 +2,7 @@ package storage
 
 import (
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -278,7 +279,8 @@ func (r *containerStore) Create(id string, names []string, image, layer, metadat
 	names = dedupeNames(names)
 	for _, name := range names {
 		if _, nameInUse := r.byname[name]; nameInUse {
-			return nil, ErrDuplicateName
+			return nil, errors.Wrapf(ErrDuplicateName,
+				fmt.Sprintf("the container name \"%s\" is already in use by \"%s\". You have to remove that container to be able to reuse that name.", name, r.byname[name].ID))
 		}
 	}
 	if err == nil {

vendor/github.com/containers/storage/containers_ffjson.go

@@ -1,5 +1,6 @@
 // Code generated by ffjson <https://github.com/pquerna/ffjson>. DO NOT EDIT.
 // source: containers.go
+//
 
 package storage
 

vendor/github.com/containers/storage/pkg/directory/directory_unix.go

@@ -1,4 +1,4 @@
-// +build linux freebsd solaris
+// +build linux darwin freebsd solaris
 
 package directory