Crash if no disc in drive

[https://www.google.com/accounts/o8/id?id=aitoawlw7vrimfrdvxg14x_fdyasjdl5lxrcanw]

If 'rip offset find' is run when there is no disc in the drive, morituri will crash with the following error:

$ rip offset find
Traceback (most recent call last):

File "/usr/bin/rip", line 35, in <module>

sys.exit(main.main(sys.argv[1:]))

File "/usr/lib/python2.6/dist-packages/morituri/rip/main.py", line 12, in main

ret = c.parse(argv)

File "/usr/lib/python2.6/dist-packages/morituri/extern/command/command.py", line 329, in parse

return self.subCommands[command].parse(args[1:])

File "/usr/lib/python2.6/dist-packages/morituri/extern/command/command.py", line 329, in parse

return self.subCommands[command].parse(args[1:])

File "/usr/lib/python2.6/dist-packages/morituri/extern/command/command.py", line 300, in parse

ret = self.do(args)

File "/usr/lib/python2.6/dist-packages/morituri/rip/offset.py", line 95, in do

runner.run(t)

File "/usr/lib/python2.6/dist-packages/morituri/common/task.py", line 390, in run

raise TaskException?(task.exception, message=task.exceptionMessage)

morituri.common.task.TaskException?: (DeviceOpenException?('Unit not ready, giving up.\nCannot setup device /dev/cdrom.',), None)

[thomas]

In [459]:

• morituri/rip/main.py: Give a nice error message if cdrdao cannot read the disc. Fixes #62.