Removed unused instance object helper function

Remove code that is no longer used

Change-Id: Iaf99824ad28aa03206a997e69d9f6097ba034941
Remove _security_group_chain_name from nova/virt/firewall.py

The function _security_group_chain_name in nova/virt/firewall.py is
useless for now, just remove it.

Change-Id: I1ad7050115ad56ce7b152efbcfcc42aff8e6c3ed
Comply with new hacking 0.8 release

Fixes a couple of small issues to pass all PEP8 tests in
the new hacking release

H235  assert_ is deprecated, use assertTrue
H231  Python 3.x incompatible 'except x,y:' construct
H234  assertEquals is deprecated, use assertEqual
H301  one import per line
H302  import only modules
H233  Python 3.x incompatible use of print operator

Change-Id: I0e5e74944e2b034b223ada1b3d0be66f2a9a5722
Merge "Comply with new hacking 0.8 release"
Merge "Removed unused instance object helper function"
Merge "Remove _security_group_chain_name from nova/virt/firewall.py"
XenAPI: Speedup host_ref cannot change - get it once

The host we run on is fixed - getting this each time from XAPI
is expensive

Change-Id: Ifee9a778f3ed855ef52b001de3fc2ebbd0b972cf
XenAPI: get_info was very expensive

Getting the whole VM record is expensive and slowed down Tempest tests
significantly.  Replaced with getting each required item.

When getting power state, only need that specific value, so reduce the
calls to get_info too.

Change-Id: I93bcef5b692a531aac41518dc29d5d4f46cded65
XenAPI: Tidy calls to get_all_ref_and_rec

get_all_records is more efficient than getting them individually in the
old get_all_ref_and_rec implementation.

Replaced some cases of get_all_records with a faster and more
specific API call.

Change-Id: I4725c3f1fdebdf1737941cb7db69b19afb22df9f
XenAPI: Speedup get_vhd_parent_uuid

In many cases the VDI record has already been retrieved.
Use it rather than expensively getting a new VDI record from XAPI.

Change-Id: I469e2a415c1f1924010f47d3927ca18c45a7b8f8
XenAPI: Use get_VALUE in preference to get_record()['VALUE']

Replaces calls to get_record where only a single item is retrieved
from the record with the specific get_VALUE call.

Change-Id: I52e20c4f4c9d6a6ad019694916ee057cc96b18a6