Remove 3 unnecessary variables in scheduler

Remove 3 lines which is unnecessary because already set its value

Change-Id: I8ba107963b8798e15b6336dbe355f86d2ef505f8
Correct the keypairs-get-resp.json API sample file

Current keypair sample files 'keypairs-get-resp.json/xml contain
'keypairs' as the first key and that means its sample response
of "list keypairs" API not "get keypair" API.

The tests don't pass a keypair id, so current tests also are for
"list keypairs" API.

Details-
Below API sample files- from their name it looks like these are for
get keypair API. But in actual content of these files are written as
List keypair API response. So it create the confusion that for which
API these API sample file are. Name suggest for GET and content
suggest for LIST Keypair.

    /nova/tests/integrated/api_samples/os-keypairs/
    keypairs-get-resp.json.tpl
    /nova/tests/integrated/api_samples/os-keypairs/
    keypairs-get-resp.xml.tpl

Their API sample test cases are written corrosponding to list keypair
APIs.

This patch correct the above API sample file name from get to list
Keypair APIs.
API Sample test cases names are also modified accordingly.

Partial-Bug: 1298769

Change-Id: I88d894ff9b0f6236221fa922601b641f26a87301
Refactor network_utils to new call_xenapi pattern

Move network_utils to the new call_xenapi style, and add some unit
tests, and to make the unit reasonable, start raising NovaException.

Change-Id: I991965ffd57bf4b309cac8c6e9d4ef94f8d430f2
Merge "Remove 3 unnecessary variables in scheduler"
Merge "Correct the keypairs-get-resp.json API sample file"
Merge "Refactor network_utils to new call_xenapi pattern"