Open vSwitch ovs-vswitchd startup time increased significantly in minor versions larger than -63

Issue

After upgrading Open vSwitch to the -71 minor version for testing, one can notice a significant increase in startup time when executing systemctl restart openvswitch.

Before:

[root@overcloud-compute-dpdk-1 ovs]# time systemctl restart openvswitch

real    1m19.464s
user    0m0.009s
sys     0m0.026s

After upgrade:

[root@overcloud-compute-dpdk-1 ovs]# time systemctl restart openvswitch
A dependency job for openvswitch.service failed. See 'journalctl -xe' for details.

real    4m2.941s
user    0m0.018s
sys     0m0.057s

After testing with Red Hat provided test builds, minor versions -56 to -71, the culprit was identified as a patch that was introduced with openvswitch-2.9.0-63.el7fdn.x86_64.