Fix error message.

Replace

| root@grml ~ # grml2usb --fat16 /live/image /dev/sdb1 --bootoptions="ssh=secret" --grub
| Executing grml2usb version 0.13.0
| Are you sure you want to format the specified partition with fat16? y/N y
| Note: you can skip this question using the option --force
| Formating partition with fat16 filesystem
| mkfs.vfat 3.0.13 (30 Jun 2012)
| Using /live/image as install base
| Error: could not find grml-version file.
| Traceback (most recent call last):
|   File "/usr/sbin/grml2usb", line 1738, in <module>
|     main()
|   File "/usr/sbin/grml2usb", line 1715, in main
|     install(iso, device)
|   File "/usr/sbin/grml2usb", line 1444, in install
|     install_grml(iso_mountpoint, device)
|   File "/usr/sbin/grml2usb", line 1478, in install_grml
|     grml_flavours = identify_grml_flavour(mountpoint)
|   File "/usr/sbin/grml2usb", line 1112, in identify_grml_flavour
|     raise
| TypeError: exceptions must be old-style classes or derived from
| BaseException, not NoneType
| 1 root@grml ~ #

with

| root@grml ~ # grml2usb --fat16 /live/image /dev/sdb1 --bootoptions="ssh=secret" --grub
| Executing grml2usb version 0.13.0
| Are you sure you want to format the specified partition with fat16? y/N y
| Note: you can skip this question using the option --force
| Formating partition with fat16 filesystem
| mkfs.vfat 3.0.13 (30 Jun 2012)
| Using /live/image as install base
| Error: could not find grml-version file.
| Cleaning up before exiting...
| 1 root@grml ~ #
Exit with better error message if running with toram=... and invoking with /live/image

If running in RAM mode without all the files in /live/image
(happens if using boot option "toram=....squashfs", but NOT when
using just "toram"!) then there are several files missing. We
could use kernel + initrd from /boot, but files like logo.16
aren't available at all. Inform the user about this situation and
possible workarounds.
Release new version 0.13.2
grml2iso: use absolute path for working directory to not fail when user specified relative path

Otherwise using for example:

| # grml2iso -t builddir ...

fails with:

| isohybrid version supports --uefi option, enabling
| Creating dd-able ISO using isohybrid
| isohybrid: [snip]/image.iso: unable to find efi image
Verify that the bootflag is enabled
Bump Standards-Version to 3.9.4
Release new version 0.13.3

Using distribution 'experimental' to keep unstable open
for possible uploads targeting wheezy.
Add realpath to Depends as it's required by grml2iso
Do not use partition for bootflag check but disk itself

A device like /dev/sdX1 won't have a bootflag enabled, so instead
look for the bootflag on the corresponding /dev/sdX device instead.

Tested-by: Markus Rekkenbeil
Mention /lib/live/mount/medium for new live path + adjust ISO versions

Debian's live-boot changed the path from /live/image to
/lib/live/mount/medium, so adopt our code to support those
new versions without breaking older ISOs.

While at it raise ISO names from version 2009.10 to upcoming 2013.01.
Release new version 0.13.4
fix detection of strange (xxxNpM) structures when finding the device for a partition [Closes: issue1244]
Release new version 0.13.5
grml2iso: make sure to exit properly if provided argument to -c option does not exist

Otherwise we're hiding the actual error message.
Make sure modprobe executable can be accessed

If /sbin is missing in $PATH then we fail with a traceback otherwise
grml2iso: provide more user-friendly error message if grml2usb executable is not available
Normalize temporary working directory to not fail with relative directory path

When invoking "grml2is -t tmpdir ..." then the kernel and
initrd files receive a wrong leading directory path on the
resulting ISO, leading to a broken ISO. Since specifying
a relative path ("-t tmpdir" instead of "-t ${PWD}/tmpdir")
should be possible as well let's just normalize it.
Release new version 0.13.6