Various bug-fixes with kernel installs.

Fixed a typo causing grub list to not incrament and other issues
with finding a reliable uname string via inspecting RPM directly.

Signed-off-by: Sandon Van Ness <sandon@redhat.com>
I seem to recall mentioning this before but it was just for better readability.

Yes using the same StringIO object should be fine but it appends to it thus the truncate...