test rebuild with openjdk-8, build log analysis and bug filings needed

[Matthias Klose <doko@debian.org>]

results from a test rebuild with openjdk-8 as the default can be found at

  https://people.debian.org/~doko/logs/20140912/

using the packages from

  deb https://people.debian.org/~doko/tmp/20140820 ./

I won't have time to analyse the results and file bug reports until mid October,
so please go ahead.  plus I'm not sure if the transition would be a good thing
for jessie. See #760984.  Having openjdk-8 in backports without any commitment
on security updates seems to be the better option.

  Matthias