grml2iso: execute under pipefail
Quoting from bash(1):
| The return status of a pipeline is the exit status of the last
| command, unless the pipefail option is enabled. If pipefail is enabled,
| the pipeline's return status is the value of the last (rightmost)
| command to exit with a non-zero status, or zero if all commands exit
| successfully.
Furthermore, move the "set -e" to the beginning of the file, to ensure
it's active as soon as possible.
While at it, drop trailing whitespace and update ISO name to a more
recent one.
This work was funded by Grml-Forensic.