fix e2e test failure

it is possible for layers.names to be nil and we must account for that.

Signed-off-by: baude <bbaude@redhat.com>

libpod/image/image.go

@@ -841,15 +841,17 @@ func (i *Image) History(ctx context.Context) ([]*History, error) {
 				delete(topLayerMap, layer.ID)
 			}
 		}
-
-		allHistory = append(allHistory, &History{
+		h := History{
 			ID:        id,
 			Created:   oci.History[x].Created,
 			CreatedBy: oci.History[x].CreatedBy,
 			Size:      size,
 			Comment:   oci.History[x].Comment,
-			Tags:      layer.Names,
-		})
+		}
+		if layer != nil {
+			h.Tags = layer.Names
+		}
+		allHistory = append(allHistory, &h)
 
 		if layer != nil && layer.Parent != "" && !oci.History[x].EmptyLayer {
 			layer, err = i.imageruntime.store.Layer(layer.Parent)

pkg/api/handlers/images_build.go

@@ -19,12 +19,6 @@ import (
 )
 
 func BuildImage(w http.ResponseWriter, r *http.Request) {
-	// contentType := r.Header.Get("Content-Type")
-	// if contentType != "application/x-tar" {
-	// 	Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest, errors.New("/build expects Content-Type of 'application/x-tar'"))
-	// 	return
-	// }
-
 	authConfigs := map[string]AuthConfig{}
 	if hasHeader(r, "X-Registry-Config") {
 		registryHeader := getHeader(r, "X-Registry-Config")