This patch adds global_request_id to the constructor for nova client,
keystone client, neutron client and placement client which will pass the
global_request_id to these respective services on all API calls.
Supporting global_request_id makes debugging easier when requests reach
many different OpenStack services. The blazar global_request_id will be
sent to these services in the request header like below and it will be
available with context.global_request_id:
-H "X-OpenStack-Request-ID: req-1a9b7b24-02ed-4400-bcc3-cc1bcbb59147"
Sample log output of neutron service for ``POST v1/floatingips`` API
which logs global request ID `req-e19f8f4f-40e7-441e-b776-7b43ed15c7dd`
is shown at: http://paste.openstack.org/show/753807
Oslo spec I65de8261746b25d45e105394f4eeb95b9cb3bd42
Change-Id: I5bb3631c4fb178293ee8eefbe1aa8b819a196a9f
563e4a8da2