Use tumbleweed as base image for worker

Author: SergioAtSUSE

worker-x86_64/Dockerfile

@@ -1,11 +1,7 @@
-FROM opensuse:42.3
+FROM opensuse:tumbleweed
 LABEL maintainer Sergio Lindo Mansilla <slindomansilla@suse.com>
-LABEL version="2017-11-16"
+LABEL version="2017-12-11"
 
-# At the moment, the only reliable source repository to install openQA is its
-# devel project in OBS.
-RUN zypper ar -f obs://devel:openQA/openSUSE_Leap_42.3 devel-openQA
-RUN zypper ar -f obs://devel:openQA:Leap:42.3/openSUSE_Leap_42.3 devel-openQA-perl-modules
 RUN zypper --gpg-auto-import-keys ref
 RUN zypper --non-interactive in qemu-kvm
 RUN zypper --non-interactive in openQA-worker