Handle the init upgrade/switch to systemd (ex: Debian 7 -> Debian 8)

[unixfox]

If a box with vlany installed and running on Debian 7 upgrade to Debian 8 the box will never reboot because of the bug with udev (a component of systemd) or if a box running any distribution switch to another init manager (Gentoo gives the ability to do this: https://elatov.github.io/2015/02/upgrade-gentoo-to-use-systemd/) the same bug will appears.

There are a few method to prevent the brick:

• On Debian based distribution, force wheezy by default: APT::Default-Release.
• Scanning the box each minute to detect systemd binaries and if detected apply a patch (?).
• Detecting changes made to the bootloader by for example on Grub2 scanning if the argument GRUB_CMDLINE_LINUX is modified and if detected apply a patch.
• Another idea (?)

[unixfox]

I'm dumb, the install.sh fix grub to mount the boot directory to read write even if the box isn't running on systemd.