Description of problem:
the env COMMIT_INTERVAL does not work when router dynamic changes enabled

Version-Release number of selected component (if applicable):
openshift v3.11.0-0.10.0
kubernetes v1.11.0+d4cacc0

How reproducible:
always

Steps to Reproduce:
1. enable dynamic changes and set COMMIT_INTERVAL
$ oc set env dc/router ROUTER_HAPROXY_CONFIG_MANAGER=true COMMIT_INTERVAL=300s
2. create your project, pod, svc and route.
$ oc create -f https://raw.githubusercontent.com/openshift-qe/v3-testfiles/master/routing/caddy-docker.json
$ oc create -f https://raw.githubusercontent.com/openshift-qe/v3-testfiles/master/routing/edge/service_unsecure.json
$ oc expose svc service-unsecure
3. check the router reloaded in logs
$ oc logs router-x-xxxxx

Actual results:
wait more than 300s but no router reloaded in logs, the route is reachable but settings are not committed to haproxy.conf

Expected results:
the dynamic changes should be committed to haproxy.config in COMMIT_INTERVAL.

Additional info:
try to use the default 3600s setting (do not set COMMIT_INTERVAL env), wait for more than one hour but no router reloaded.  

code:
// defaultCommitInterval is how often (in seconds) to commit the "in-memory"
// router changes made using the dynamic configuration manager.
const defaultCommitInterval = 60 * 60