[ Merge of http://go/wvgerrit/149130 ]
When re-initializing OEMCrypto for testing purposes, the
UsageTableHeader must be reset as well. This is to inform future
sessions to load or create a new header before creating new entries.
Bug: 219075437
Test: request_license_test and MediaDrmTests GTS
Change-Id: Ie8bc72bc7ea079d21587e114223fcb67547c756a