RaSCSI doesn't allow CD images to be inserted

[akuker]

There seems to be some odd behavior with RaSCSI trying to insert/eject removable media (it may exist with other types as well).

The following commands were flagged as "invalid", but they should have worked.
pi@rascsi:~ $ rasctl -i 0 -c insert /home/pi/Downloads/ubuntu-20.04-desktop-amd64.iso
Error : Invalid file path
pi@rascsi:~ $ rasctl -i 0 -c insert /home/pi/Downloads/SSW-71-Universal/Hd-100.iso
Error : Invalid file path

[akuker]

The code appears to have been reporting "fail" when it succeeded, and "success" when the open failed. Added the '!' to match the previous file open call.