tools: don't try to grab the device for evemu-describe

evemu-describe doesn't care if there's a grab on the device, it still sees the
description.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
tools: disabling a device removes the grab too, note that in the man page

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
tools: refer to the man page for the grab warning message

might as well say that we have the documentation available, rather than
expecting people to google.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
tools: refer to fuser to detect who's got the grab

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>