bug: 12228689
If the device ID returned from OEMCrypto_GetDeviceUniqueId is
not NULL terminated in the OEM code, trailing garbage characters
may be included in the license request's client_identification
field, which could be rejected by the server's utf8 parser if
they are invalid characters, causing a license request failure.
The code for CryptoSession::GetDeviceUniqueId should use the
updated id_length from OEMCrypto_GetDeviceUniqueId to adjust
the length of the *device_id string before returning the result
to the caller.
Change-Id: I659866d4234d4f21ec051590fc7bc6367904a48a