Sync request_id middleware for nova

This piece of middleware generates and attaches a request_id to
a request, to be used in completing the blueprint
cross-service-request-id for icehouse.
See change Ib4a9c404cb149d8f76bde52f7613a9596b2233b9

Change-Id: Ib0b0f19b3be332f736246b472902c6b95c1264e9
Implements: blueprint cross-service-request-id
Merge "Sync request_id middleware for nova"
Merge commit 'refs/changes/53/58753/10' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/54/58754/12' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/55/58755/11' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/61/58861/11' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/53/60253/7' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch

Conflicts:
	nova/virt/xenapi/vm_utils.py
Merge commit 'refs/changes/08/60808/6' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/78/63778/1' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/38/66338/7' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/97/66597/3' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch