The main goal of this patch is to move Tempest context related code
from the rally/plugins/openstack/verification/tempest/config.py file
to the separate rally/plugins/openstack/verification/tempest/context.py
file.
Also,
1. Functions such as 'add_extra_options' and 'extend_configfile' were
moved from the rally/plugins/openstack/verification/tempest/config.py
file to rally/verification/utils.py because these functions can be
used by other verifier plugins in the future.
2. Now Tempest log, test image and lock files are stored in the
corresponding deployment directory.
3. Now the 'floating_network_name' option from the 'network' section is
configured as well.
4. A small cleanup was done.
Change-Id: I12c7918400c736b71c5a8044bb1aa53122fb96f1
ac4ddc4c72