Merge "Fix default keymaster so it doesn't start an extra thread." into pi-dev

using android::hardware::keymaster::V4_0::SecurityLevel;

int main() {

    ::android::hardware::configureRpcThreadpool(1, true /* willJoinThreadpool */);

    auto keymaster = ::keymaster::V4_0::ng::CreateKeymasterDevice(SecurityLevel::SOFTWARE);

    auto status = keymaster->registerAsService();

    if (status != android::OK) {