dhcp_lease_time and dhcp_lease_duration should be a single config option

[Darren Birkett]

This is somewhat related to https://bugs.launchpad.net/quantum/+bug/1116500 where this issue was brought up but never fixed.

The dnsmasq dhcp agent uses the setting 'dhcp_lease_time' (default 120s)

The db plugin uses the setting from dhcp_lease_duration (default 120s)

It seems to me that there is a potential for bad things to happen if one (_duration) is set a lot shorter than the other (in that the db may expire a lease that dnsmasq still considers valid).

To prevent the potential for such bad things, these settings should become one single setting used everywhere.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/33647

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/33647
Committed: http://github.com/openstack/quantum/commit/95dbd03a0bc4867bf8520539ed08f4068adf2f33
Submitter: Jenkins
Branch: master

commit 95dbd03a0bc4867bf8520539ed08f4068adf2f33
Author: Darren Birkett <email address hidden>
Date: Wed Jun 19 12:37:02 2013 +0000

    replace use of dhcp_lease_time with dhcp_lease_duration

    Having 2 separate dhcp lease period flags (dhcp_lease_duration
    used by the quantum db plugin, and dhcp_lease_time used by the
    dnsmasq dhcp agent) means that you could potentially have different
    lease periods being set, and used by different parts of the codebase.

    It seems to me there is no real need to have 2 separate flags, so this
    commit basically replaces references to dhcp_lease_time (which is used
    by the dnsmasq dhcpagent) with dhcp_lease_duration. This way, there
    is only one flag to set, and both the quantum db plugin and dnsmasq
    dhcp agent will use the same lease period.

    Change-Id: Ia99dfa9284b6e737144f61a80c59cd898c0949bb
    Fixes: bug #1192550