Replace assert* with more suitable asserts in tests

The following replacements were done in unit tests to
 have clearer messages in case of failure:
- assertTrue(a == b or a == c) with assertIn(a, [b, c])
- assertTrue(type(a) == dict) with assertIsInstance(a, dict)
- assertTrue(type(a) == int) with assertIsInstance(a, int)

Also assertTrue with several conditions was splitted.

Change-Id: Id6e5db9ead8d8dceb9f416c1b55280855d25e604
Replace assertTrue/False with assertEqual/NotEqual

The following replacements were done in tests to have
clearer messages in case of failure:
- assertTrue(* == *) with assertEqual
- assertTrue(* != *) with assertNotEqual
- assertFalse(* == *) with assertNotEqual

Change-Id: Idbb1a292cf8545b87728fa2b815c67f923ef6efa
Add aggregates.rst to devref index

aggregates.rst was the only devref document that wasn't included in any
toctree.

Change-Id: I3e4392d2571b954d4553ca8e50b02053db4b5d99
Prevent max_count > 1 and specified ip address as input

Previously, if one did:
   nova boot --num-instances 2 --nic net-id=<net_id>,v4-fixed-ip=10.0.0.17
this would result in all of the instances failing to boot because neither
nova-network or neutron allows multiple instances to have the same ip_address.
This patch fixes this from occuring by checking for this and raising an error
to the caller from nova-api.

Change-Id: I7e44d58e66aeb10fb15c3553072f988f65ab823b
Closes-bug: 1318754
Merge "Prevent max_count > 1 and specified ip address as input"
Merge "Replace assert* with more suitable asserts in tests"
Merge "Add aggregates.rst to devref index"
Merge "Replace assertTrue/False with assertEqual/NotEqual"