Keystore 2.0: Fix loading of unencrypted legacy super keys. In 2019 we had a bug that caused super keys to remain unencrypted. This CL accounts for the existance of such unencrypted keys. Bug: 183591049 Bug: 141955555 Change-Id: I2ebca684e7d5bd1269c26cf3d06ed380d1ee4770 (cherry picked from commit 87dbe0072cc58521b0b28aac71dd49db7b1f60dd)