Fix the grub2 config location for non Ubuntu/Debian systems

Fedora and openSUSE use /boot/grub2/grub.cfg for the grub2
configuration. The path that was used for Fedora before
(/boot/grub/grub.conf) is only valid for older grub releases.

Change-Id: I1e532c73a373a2c3f92211eff52719c2b635b7e3
Merge "Fix the grub2 config location for non Ubuntu/Debian systems"