Change the default value for the config blazar_az_prefix

Current default value for the config 'blazar_az_prefix' is 'blazar:'.
However, ':' should not be included in the name of availability zones.

According to the parse_availability_zone() [1] of the API class of Nova,
there is a legacy hack to allow admins to specify hosts via an
availability zone using az:host:node. That means ':' cannot be included
in the name of an availability zone itself. But Nova accepts the
invalid name with ':'. That is reported as a bug [2].

This patch changes the default value for the config blazar_az_prefix
from 'blazar:' to 'blazar_' which does not use ':'.

[1] https://review.openstack.org/gitweb?p=openstack/nova.git;a=blob;f=nova/compute/api.py;h=46ed8e91fcc16f3755fd6a5e2e4a6d54f990cb8b;hb=HEAD#l561
[2] https://bugs.launchpad.net/nova/+bug/1695861

Partial-Bug: #1695862
Change-Id: Iaff0b8e576dbcb56b89384ea236c3f121d4ffad1

blazar/plugins/oshosts/host_plugin.py

@@ -42,10 +42,9 @@ plugin_opts = [
                deprecated_since='0.3.0',
                help='Actions which we will use at the start of the lease'),
     cfg.StrOpt('blazar_az_prefix',
-               default='blazar:',
+               default='blazar_',
                deprecated_name='climate_az_prefix',
-               help='Prefix for Availability Zones created by Blazar'),
-
+               help='Prefix for Availability Zones created by Blazar')
 ]
 
 CONF = cfg.CONF

devstack/plugin.sh

@@ -84,6 +84,10 @@ function configure_blazar {
     fi
     iniadd $NOVA_CONF filter_scheduler available_filters "blazarnova.scheduler.filters.blazar_filter.BlazarFilter"
 
+    # TODO(hiro-kobayashi): This line should be deleted after the patch
+    # https://review.openstack.org/#/c/471590/ is merged.
+    iniadd $NOVA_CONF blazar:physical:host blazar_az_prefix blazar_
+
     # Database
     recreate_database blazar utf8