.deb build as jenkins test

Hi. In a light of https://projects.osmocom.org/issues/2340 I'd like to add .deb build as an additional step for jenkins jobs triggered by gerrit push. It'll mean longer build times but it'll prevent breaking changes from reaching master. It won't guarantee that we won't see occasional arch/version specific breakage in https://build.opensuse.org/project/monitor/network:osmocom:nightly but it should make nightly builds more stable and easier to maintain. What do you think? -- Max Suraev <msuraev(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Alt-Moabit 93 * 10559 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschaeftsfuehrer / Managing Director: Harald Welte