Use buildah commit and bud in podman

Vendor in buildah and use as much of commit and bug as possible for podman
build and commit.

Resolves #586
Signed-off-by: baude <bbaude@redhat.com>

Closes: #681
Approved by: mheon

vendor/github.com/fsouza/go-dockerclient/distribution.go

@@ -0,0 +1,26 @@
+// Copyright 2017 go-dockerclient authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package docker
+
+import (
+	"encoding/json"
+
+	"github.com/docker/docker/api/types/registry"
+)
+
+// InspectDistribution returns image digest and platform information by contacting the registry
+func (c *Client) InspectDistribution(name string) (*registry.DistributionInspect, error) {
+	path := "/distribution/" + name + "/json"
+	resp, err := c.do("GET", path, doOptions{})
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	var distributionInspect registry.DistributionInspect
+	if err := json.NewDecoder(resp.Body).Decode(&distributionInspect); err != nil {
+		return nil, err
+	}
+	return &distributionInspect, nil
+}