kexec-load incorrectly parses grub.cfg

When USE_GRUB_CONFIG is set to "true" in /etc/default/kexec, reboot hangs with scrambled screen somewhere on kernel load.

This is due to incorrect parsing of /boot/grub/grub.cfg performed in /etc/init.d/kexec-load. In 12.10 grub.cfg contains submenues, which have their own 'menuentry' records. Incorrect parsing brings wrong kernel parameters (from the last record, which is 'recovery mode').

As grub.cfg is generated file, I would expect that kernel, initrd and parameters are fetched with the same algorithm that generate grub.cfg.

$ lsb_release -rd
Description: Ubuntu 12.10
Release: 12.10

$ apt-cache policy kexec-tools
kexec-tools:
  Installed: 1:2.0.3-1ubuntu2
  Candidate: 1:2.0.3-1ubuntu2
  Version table:
 *** 1:2.0.3-1ubuntu2 0
        500 http://ru.archive.ubuntu.com/ubuntu/ quantal/main amd64 Packages
        100 /var/lib/dpkg/status