[Review] Request from 'schubi2' @ 'yast/yast-kdump/review_140721_crashkernel_param_value'

Please review the following changes:
  * 953e66f packaging
  * 4819be9 reading crashkernel_param_value correctly

The comment is a bit misleading, why not something like

    # Read the current value only if crashkernel parameter is set

maybe something better? The problem is how the code is cryptic, it took me a while to understand it and I had to find what are possible return values from `Bootloader.kernel_param`. Maybe adding a comment at the top of the function (what are the possible return values would help a lot) ~ near to Bootloader.kernel_param call?