Log cleanups for nova.network.neutron.api

This patch adds hints for log error and warning levels.

TrivialFix

Change-Id: Ibd516b41cc40afafe2dc37cdc5657d494c33c2cf
Fix live-migration failure in FC multipath case

Currently, /dev/dm-<NUM> instead of /dev/mapper/<multipath_id> is
used to access multipath FC volumes by Compute Node and
multipath_id in connection_info is not maintained properly and
may be lost during connection refreshing.

This implementation will make source Compute Node and destination
Compute Node fail to disconnect/connect to volumes properly and
result in live-migration failure.

To fix it, /dev/mapper<multipath_id> will be used instead of
/dev/dm-<NUM> to access multipath devices, just like iSCSI multipath
implementation, and logic to preserve the unique (across Compute
Nodes) multipath_id is also added.

Change-Id: I17f15852c098af88afd270084c62eb87693c60d4
Closes-Bug: #1327497
Merge unit tests of "create a flavor" API

In test_flavor_manage, there are success/bad_request tests of
"create a flavor". Most parts of them are duplicated.
This patch merges them for the readability and clarifying their
purposes.

Change-Id: Ic7fa319674594f4470b6eafd3e07e7c467b99477
Add new db api get functions for ec2_snapshot

This patch adds two new getters for EC2 snapshot mappings to the db
API.  The existing getters don't return the full db model.  Instead,
they only return an ID or UUID.  The full db model is needed when this
gets converted over to a nova object.

Related to blueprint convert-ec2-api-to-use-nova-objects

Change-Id: I8e2ed5086a7768f373d35c2f34386f2d30d11e07
Merge "Fix live-migration failure in FC multipath case"
Merge "Add new db api get functions for ec2_snapshot"
Merge "Merge unit tests of "create a flavor" API"
Merge "Log cleanups for nova.network.neutron.api"