We've tried our best to protect against malicious storage devices with limited SELinux domains, but let's be even more paranoid and refuse to look at disks inserted while a secure keyguard is showing. We'll gladly scan them right away once the user confirms their credentials. Test: builds, boots, manual testing Bug: 68054513 Change-Id: I19b7446e855176921ed477ef6d07bc9a2cc0ef9a