CI: Modify jjb in releng to use vsperf build script for the nightly build

CI: Modify jjb in releng to use vsperf build script for the nightly build

This patch removes calling of scl and vsperf from 'verify'
and 'merge' jobs. The reason is that both jobs are started
on 'opnfv-build' and environment on all boards is not
set to run the vsperf.

JIRA: VSPERF-156

Signed-off-by: Radek Zetik <radekx.zetik@intel.com>
Reviewed-by: Aric Gardner <agardner@linuxfoundation.org>
Reviewed-by: Xinyu Zhao(Jerry) <zhaoxinyu@huawei.com>
Reviewed-by: Fatih Degirmenci <fatih.degirmenci@ericsson.com>
Reviewed-by: Ulrich Kleber <Ulrich.Kleber@huawei.com>
Reviewed-by: Billy O Mahony <billy.o.mahony@intel.com>