docs/system/devices/usb: Replace the non-existing "qemu" binary

We don't ship a binary that is simply called "qemu", so we should
avoid this in the documentation. Use the configurable binary name
via "|qemu_system|" instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
1 file changed