DO NOT MERGE: Bump CTS and CTS Verifier to 6.0_r15 am: 1100322fee  -s ours am: e6e8171682 am: 1066a1cc2e am: 15b6e9813e
am: df0ce29579  -s ours

Change-Id: I37529739a8153449bbbe83d0d44115560e9499d8