Bug#751012: [flash-kernel] Flash-kernel should fail with exit 0 under debrootstrap

[bastien ROUCARIES <roucaries.bastien@gmail.com>]

Package: flash-kernel
Severity: important

Flash-kernel should detect it run under debrootstrap and fail gracefully/

Install message:

Processing triggers for libc-bin (2.18-7) ...
Processing triggers for initramfs-tools (0.115) ...
update-initramfs: Generating /boot/initrd.img-3.14-1-kirkwood
/bin/df: Warning: cannot read table of mounted file systems: No such file or directory
warning: failed to read mtab
^Cdpkg: error processing package initramfs-tools (--configure):
 subprocess installed post-installation script was interrupted
Errors were encountered while processing:
 initramfs-tools
E: Sub-process /usr/bin/dpkg returned an error code (1)