CQM lintian: spelling.
Fix check_disp_hdparm_cap(): exclude pseudo usb disks (Raphaël Halimi).
Fix issue #94: do not touch sleeping hybrid radeon graphics
    with radeon dpm and runtime pm (Lathanderjk)
get_drivebay_device grep command to suppress errs.

get_drivebay_device grep command to suppress errors with `2> /dev/null`;
before if file didn't exist, error message was shown.

Signed-off-by: Thomas Koch <linrunner@gmx.net>