Cleanup and gate on hacking E713 rule

This fixes the offending instances of the rule
and removes it from the ignore list in tox.ini
so that we can gate on the E713 rule.

Change-Id: I1f9ef23a8569252b5b6fa660d0d200b1702056d0
Make BDM dict __init__ behave more like a dict

Currently we can't pass values as kwargs to BlockDeviceDict classes.
This is a common way to call a dict constructor so it breaks the dict
abstraction a bit.

This patch fixes it in a backward compatible way.

Change-Id: I31117eecba4f060cb9c7fc3d329f70fd369b168d
VMware: Consolidate fake_session in test_(vm|ds)_util

Both test_vm_util and test_ds_util contained a fake_session class.
The implementation of test_ds_util.fake_session was irrelevant to
almost all of its users, which was confusing.

fake_session from these 2 modules is consolidated into fake. We now
have fake.FakeSession(), which expects _call_method and _wait_for_task
to be mocked, and fake.FakeObjectRetrievalSession(), which is a
utility object for faking the return of an object list.

The implementation details of test_ds_util.fake_session have been
pushed into test_file_exists and test_file_exists_fails, where they
belong.

Change-Id: I168af46d28629c8b2cf8adae856f0f66ae3ee922
libvirt: speed up _get_disk_over_committed_size_total method

Switch the _get_disk_over_committed_size_total method to
use the new list_instance_domains method.

Blueprint: libvirt-domain-listing-speedup
Change-Id: I4ef00ea5584eda14c4781d3fbf8bb737f3abdc90
Merge "Cleanup and gate on hacking E713 rule"
Merge "Make BDM dict __init__ behave more like a dict"
Merge "VMware: Consolidate fake_session in test_(vm|ds)_util"
Merge "libvirt: speed up _get_disk_over_committed_size_total method"