Add basic quota tests

    This is the second part of the patch series to implement the
quota tests. It builds on the refactor work, and implements
three simple tests. tempest.conf.sample is updated to enable
a large enough CIDR to permit the default quota to be reached
for ports.

    Implements: blueprint quantum-quota-basic-tests quota tests
    Change-Id: Ibb93a3367f5a2e36a1022f0f427771c727b609d6

Change-Id: I412f2272bfcab8b9c7e7c848bcb0b6146df2874d
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index 02bfdcb..9280c57 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -178,7 +178,7 @@
 tenant_network_cidr = 10.100.0.0/16
 
 # The mask bits used to partition the tenant block.
-tenant_network_mask_bits = 29
+tenant_network_mask_bits = 28
 
 # If tenant networks are reachable, connectivity checks will be
 # performed directly against addresses on those networks.