Minor cleanup for the quantum_l3_ovs_bridge provider.

 * Use each() instead of collect() when iterating in
   bridge_ip_addresses.
 * Update the property_hash's value for ensure when the resource
   is created or destroyed.

Change-Id: Ib62c74c7a9ba38bdd57b263eeee94f370611b8b9
Default to using the catalog for tenant lookup.

 * Only if the tenant cannot be found in the catalog will instances
   be used.
 * Replaced the get_tenant_id method in the providers with an inline
   call since it is only needed for create()

Change-Id: I1bb4b6d9998f9d334df10bf9b1f683c4f2f38150
Fix parsing of resource creation output.

 * The results of resource creation were previously not being
   parsed at all, so that new instances would not have their
   property_hash properly populated.  This change ensures
   correct property_hash population.
 * Stop using an instance variable when a local variable (attrs)
   with do.

Change-Id: I88fe3ba964839762d5ad6a431d3d9ab876266fe9