findbugs-bcel-5.2-bp151.3.1

- Specify java source and target level 1.6 in order to allow
  building with jdk9

- Remove gpg-offline dep and rely on service

- Fix build on SLE11 and cleanup with spec-cleaner

- Move from jpackage-utils to javapackage-tools

- Fix gpg verification to actually pass on factory so we can merge
  more java fixes.

- add pointless _constraints, which turn off scheduling on buildXY hosts
- use pristine tarballs
- fix source url
- add gpg verification
- format spec file

- Initial packaging of findbugs-bcel (taken from Fedora)