Change LinuxAdmin.run to return a CommandResult object.

Added LinuxAdmin.run! behaves similar to the old run's functionality in that it raises an exception on failure.
CommandResultError is raised on a non-zero exit status.
The failed system call exception is raised on a bad command such as: Errno::ENOENT: No such file or directory.
Update disk/system related classes to use the new run! and run interface.

run was changed to run! in cases where the prior run would have raised an exception.
Update package related classes to use the new run! and run interface.

run was changed to run! in cases where the prior run would have raised an exception.