Update gate job to stop cloning old gnocchi location.
Update gate job to stop cloning old gnocchi location.

file: jenkins/jobs/collectd-ceiloemter-plugin.yaml

The location specfied in the local.conf section of the
collectd-ceilometer-plugin job point to gnocchixyz/gnocchi (current
location).
However, this is overwritten by "openstack/gnocchi" specified in the
PROJECTS variable.

This remove the reference to gnocchi in the PROJECTS variable.
Change-Id: I0b0775ad111ba1b225d77c56c71a0da67a96ab57

openstack-infra/project-config,openstack-infra/project-config