Refactored kernelCmdLinePackages to rely on .proc.cmdline agent (bnc#889365)

this is very tricky and to be honest I do not like it much. Better approach for me is
```
biosdevname = options.grep(/^biosdevname=/i).first
if biosdevname
  value = biosdevname[/^biosdevname=(\d+)/i, 1]
  ...
else #missing biosdevname
```