[ibr-dtn] [patch] abort if something fails during configuration

Hi list,

I haven't found an official contribution guideline, so please find attached a trivial patch that aborts autogen.sh if a step fails.

By the way, why are all the configuration files starting with #!/bin/bash instead of #!/bin/sh ? I haven't found a single bashism so far, just outdated `command` instead of $(command).

Cheers,

Philipp