Add log output of "x-openstack-request-id" from nova

This patch enables ceilometer to output
'x-openstack-request-id'/'x-compute-request-id'
of nova's responses to the log.
And it also enables ceilometer to output
request headers, request parameters,
other response headers and a response body to
the log when ceilometer calls nova.

DocImpact: There is a new configuration option
'nova_http_log_debug' in ceilometer.nova_client

Change-Id: Ic7e5301e46ac45597721f4a9b41c38f8c4ff0d14
Closes-bug: #1332060
Merge "Add log output of "x-openstack-request-id" from nova"