Fix pairing aes_128_gcm key initialization.

Bug: 150719467

Test: atest adb_pairing_auth_test
Test: check 'adb pair' command on all three platforms work
Change-Id: Idfc64fe7bed2d09f4da9d2f7df70f9d6ae4e8fa3
Exempt-From-Owner-Approval: approved in go/ag/10808153
7 files changed