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/Microsoft/hcsshim/internal/hcs/schema2/keyboard.go

@@ -0,0 +1,13 @@
+/*
+ * HCS API
+ *
+ * No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)
+ *
+ * API version: 2.1
+ * Generated by: Swagger Codegen (https://github.com/swagger-api/swagger-codegen.git)
+ */
+
+package hcsschema
+
+type Keyboard struct {
+}