Add quota table in PLUMgrid plugin

Quota DB driver is enabled in Neutron by default.
PLUMgrid plugin was missing the "quota" table. It has
been added in this commit.

Fix bug# 1236970

Change-Id: I5170a8be2b412a3bcf1edcacce5574f0073b84d4
(cherry picked from commit 23bec4f7cb6e84a8d717c0b5ccc222f51c67f072)
Merge "Add quota table in PLUMgrid plugin" into milestone-proposed