Log a warning if dnsmasq version is below the minimum required

It has been noted that older versions of dnsmasq may have unexpected
behavior, so this patch introduces a check on dnsmasq version; if
the minimum version is not met, a warning is logged. This is less
invasive than raising an Exception and abort the dhcp agent, even
though this also seems like a perfectly acceptable behavior.

Fixes bug 1170793

(cherry picked from commit 364032897293256436647cb89c61a3dffb408946)

Aforementioned cherry-pick has sudo issues hence the additional one
(cherry picked from commit 91b56e41eecf2cd8b4c848b4e773a1be307b40c3)

Change-Id: I8475afc6bdd6145d2a491177af080fee960cb3e6
Enable quantum-netns-cleanup to receive force as cli parameter

Fixes bug 1180767

Change-Id: Icd58fbe995129806426b70ea54d98f213988dbe5
(cherry picked from commit 7c82107f0aaee3e8624e3b3baddfe09b96b9d804)
Merge "Log a warning if dnsmasq version is below the minimum required" into stable/grizzly
Merge "Enable quantum-netns-cleanup to receive force as cli parameter" into stable/grizzly
Merge branch 'stable/grizzly' of https://github.com/openstack/quantum into iteco