Concurrent true for opnfv-yamllint-verify-master

Concurrent true for opnfv-yamllint-verify-master

this patchset https://gerrit.opnfv.org/gerrit/#/c/26517/10

build logs:

Building remotely on lf-build1 (opnfv-build-centos opnfv-build
opnfv-sysinfo ci-resource) in workspace
/home/jenkins-ci/opnfv/slave_root/workspace/opnfv-yamllint-verify-master

FATAL: The project is configured to NOT run builds concurrent, but the
node parameter [SLAVE_NAME] is configured to trigger new builds
concurrent!
java.lang.IllegalStateException: The project is configured to NOT run
builds concurrent, but the node parameter [SLAVE_NAME] is configured to
trigger new builds concurrent!

linting can be done concurrently

Change-Id: Ied083c3db5c22621af121324ce5264c1851cb31e
Signed-off-by: Aric Gardner <agardner@linuxfoundation.org>