Keystore 2.0: Legacy key blobs

This patch adds support for reading legacy keystore blob files.

Test: keystore2_test
Bug: 159371296
Change-Id: I94ec556b2250a0ef7d55c317e13b3f3770a11bc7
diff --git a/keystore2/src/lib.rs b/keystore2/src/lib.rs
index e13d6c0..5ad77d1 100644
--- a/keystore2/src/lib.rs
+++ b/keystore2/src/lib.rs
@@ -21,6 +21,7 @@
 pub mod globals;
 /// Internal Representation of Key Parameter and convenience functions.
 pub mod key_parameter;
+pub mod legacy_blob;
 pub mod operation;
 pub mod permission;
 pub mod security_level;