heat rename HEAT::HA::Restarter resource

Rename HEAT::HA::Restarter to OS::Heat::HARestarter, which fits
better with the other openstack-native resources which use the
OS:: namespace

Change-Id: I40038e64979aca184971b11e83f6ef92a3b54571
Signed-off-by: Steven Hardy <shardy@redhat.com>
Merge "heat rename HEAT::HA::Restarter resource"