Comment 6 for bug 1805824

Reviewed: https://review.openstack.org/625152
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=ce2ddcbf3f0cddeb1025f4aab224d78df4554630
Submitter: Zuul
Branch: stable/queens

commit ce2ddcbf3f0cddeb1025f4aab224d78df4554630
Author: Yang JianFeng <email address hidden>
Date: Thu Nov 29 20:18:31 2018 +0800

    Fix the bug about DHCP port whose network has multiple subnets.

    When a subnet's enable_dhcp attribute is updated, we must restart
    dhcp device. So,when we decide whether 'restart' or
    'reload_allocations' in refresh_dhcp_helper function we only compare
    the cidr of subnets which enabled dhcp.

    The previous logic only calls 'restart' when deleting or adding a
    subnet. This may cause the dhcp port not updated when the subnet's
    enable_dhcp is updated to True.

    Change-Id: Ic547946ac786c5fab82b4ee7078bf86483f51eb5
    Closes-Bug: #1805824
    (cherry picked from commit 9aa7af82210f1ffb6274399648962b65162e17d1)