feat(pre-mount-gptprio): die if the kexec returns

kexec is like exec in that we should never return. If we do return then
something terrible happened. Lets stop everything and print an error.
feat(dracut): add debuggging output

logging is cheap, debugging this stuff is hard.

TODO: use INFO functions
Merge pull request #2 from philips/kexec-or-die

feat(pre-mount-gptprio): die if the kexec returns
Merge branch 'add-debug' of github.com:philips/bootengine into philips-add-debug