jenkins: force fetch on each PR.

[jcvenegas]

If a PR was updated with a push force. We need to force
to update the brach to test this commit does:

• clean current branch.
• If testing a PR, force to fetch and pull a brach with latest changes.

Fixes: #894

Signed-off-by: Jose Carlos Venegas Munoz jose.carlos.venegas.munoz@intel.com

[grahamwhaley]

lgtm
and thanks for adding the git clean as well.

[clearcontainersbot]

kubernetes qa-failed 👎

[sboeuf]

the CI is not passing...

[jcvenegas]

@chavafg @grahamwhaley any idea?

 # cd /srv/jenkins/workspace/workspace/clear-containers-tests-16.04-PR/go/src/github.com/clearcontainers/tests; git pull --ff-only
11:24:11 There is no tracking information for the current branch.
11:24:11 Please specify which branch you want to merge with.
11:24:11 See git-pull(1) for details.
11:24:11 
11:24:11     git pull <remote> <branch>
11:24:11 
11:24:11 If you wish to set tracking information for this branch you can do so with:
11:24:11 
11:24:11     git branch --set-upstream-to=origin/<branch> PR_886
11:24:11 
11:24:11 package github.com/clearcontainers/tests: exit status 1

[clearcontainersbot]

kubernetes qa-failed 👎

[clearcontainersbot]

kubernetes qa-failed 👎

[chavafg]

lgtm