update c/common

Update containers common to the latest HEAD.  Some bug fixes in libimage
forced us to have a clearer separation between ordinary images and
manifest lists.  Hence, when looking up manifest lists without recursing
into any of their instances, we need to use `LookupManifestList()`.

Also account for some other changes in c/common (e.g., the changed order
in the security labels).

Further vendor the latest HEAD from Buildah which is required to get the
bud tests to pass.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

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

@@ -323,3 +323,40 @@ func SafeLchown(name string, uid, gid int) error {
 	}
 	return checkChownErr(os.Lchown(name, uid, gid), name, uid, gid)
 }
+
+type sortByHostID []IDMap
+
+func (e sortByHostID) Len() int           { return len(e) }
+func (e sortByHostID) Swap(i, j int)      { e[i], e[j] = e[j], e[i] }
+func (e sortByHostID) Less(i, j int) bool { return e[i].HostID < e[j].HostID }
+
+type sortByContainerID []IDMap
+
+func (e sortByContainerID) Len() int           { return len(e) }
+func (e sortByContainerID) Swap(i, j int)      { e[i], e[j] = e[j], e[i] }
+func (e sortByContainerID) Less(i, j int) bool { return e[i].ContainerID < e[j].ContainerID }
+
+// IsContiguous checks if the specified mapping is contiguous and doesn't
+// have any hole.
+func IsContiguous(mappings []IDMap) bool {
+	if len(mappings) < 2 {
+		return true
+	}
+
+	var mh sortByHostID = mappings[:]
+	sort.Sort(mh)
+	for i := 1; i < len(mh); i++ {
+		if mh[i].HostID != mh[i-1].HostID+mh[i-1].Size {
+			return false
+		}
+	}
+
+	var mc sortByContainerID = mappings[:]
+	sort.Sort(mc)
+	for i := 1; i < len(mc); i++ {
+		if mc[i].ContainerID != mc[i-1].ContainerID+mc[i-1].Size {
+			return false
+		}
+	}
+	return true
+}