Add the parameter $report_interval to the ml2
networking-baremetal manifest. By default the global
report_interval as defined in neutron.conf is used.
In some cases it makes sense to change the report_interval
specifically for ironic-neutron-agent.
Related-Bug: #1940838
Change-Id: I6fc0eb085c09fb1e24ff09d4f8199d2cf57dd209