daps autobuild does not fetch (brand)new branches automatically

[taroth21]

Problem description

If you want to build documentation from a freshly created branch on GH and have added a new section for this in daps-autobuild_docserv.xml, the build process will nevertheless fail, unless you manually run a git pull in the repo on docserv first.

Expected behavior

It should work without manual interaction, even if the branch on GH has been created just a few minutes ago.

Steps to reproduce the behavior

1. Add a new branch and push it to GH.

2. Immediately afterwards, add a new section to daps-autobuild_docserv.xml to build from this branch in docserv.

3. Manually trigger a build for this section.

4. You will receive an error like the following:

    error: pathspec 'maintenance/SLEHA12SP4' did not match any file(s) known to git.
    Running 'git co <branch>' in /suse/lxbuch/doc/git/doc-sleha failed!
    Skipping SLE-HA_12_SP4