VlanManager creates superfluous quota reservations

The VlanManager does not enforce quotas on fixed IPs because it
allocates an entire network to a project. However the process
of deallocating an IP address still creates an entry in the
reservations table.

The VlanManager now loads the NoopQuotaDriver and no longer
writes superflously to the database.

Change-Id: Idf95085a5c1f4e71f3f0fc92618607073602eed3
Fixes: Bug #1204714
Merge "VlanManager creates superfluous quota reservations"