Updated openstack/openstack
Project: openstack/ceilometer  6082106bc0fa1324535e85b5fc3bcf4fb7849792

Fix the section name in CONTRIBUTING.rst

The name of the section "If you're developer, start here"
has changed in the wiki, now is "If you're a developer".
This commit updates it to correctly refer to the
proper section.

Change-Id: Ida0406aab1af92687b9e8087a328a5f0e8ce1d9a