Vendor in latest containers/buildah

Switch from projectatomic/buildah to containers/buildah

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

vendor/github.com/containers/buildah/chroot/util.go

@@ -0,0 +1,15 @@
+// +build linux
+
+package chroot
+
+func dedupeStringSlice(slice []string) []string {
+	done := make([]string, 0, len(slice))
+	m := make(map[string]struct{})
+	for _, s := range slice {
+		if _, present := m[s]; !present {
+			m[s] = struct{}{}
+			done = append(done, s)
+		}
+	}
+	return done
+}