Allow non-system server code to AppOpsManager.checkOp and NoteOp

1. Allow checkOp from any caller, not only callers with
  android.permission.UPDATE_APP_OPS_STATS. This is ok as checkOp does not
  update any stats
2. Clear the binder identity when calling noteOp so that it is checked
  if the service can perform the operation, not the caller.

Test: Verified that RecognitionService can be used by third party apps
Fixes: 152436092
Change-Id: Ie6fe90b5737a1cd24e45446ea91560940b41c8fc