utils: Git & SVN Harvester

* Harvester utils to download and archive SVN & Git repos

Signed-off-by: Jake Cowton <jake.calum.cowton@cern.ch>
utils: addition of call checks for vcs commands

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
travis: CFG_TMPDIR set to /tmp

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>