[opensuse-buildservice] Patch to bs_publish to make secure apt repository

Hi, now that I have signing up and running for RPM, I also need to have a signed apt repo. How that works can be read at http://wiki.debian.org/SecureApt I created a patch to bs_publish to generate a Release and a Release.gpg file, which is needed to secure apt. Patch is attached. Would be nice, if that patch would be included within the next release. -- With best regards, Carsten Hoeger