Small refactor to clarify auth token ownership.

The Operation interface confused me.  It looked like it was holding a
pointer to an auth token from the AuthTokenTable.  In fact it made a
copy, but that wasn't clear from the interface.  Ths CL changes
Operation::setOperationAuthtoken to take the token by value, making
clear that it copies (unless std::move is used).

Test: runtest --path cts/tests/tests/keystore/src/android/keystore/cts
Change-Id: I1d1b6983f421f5be9f56c60aaf56dda8fc4aa207
3 files changed