Set correct gateway for the bifrost provision network

In the production sometimes the provision and other networks should be
separated and all have each own different gateways, so this change adds
the correct way to configure bifrost with gateway used only to configure
dnsmasq and solves the issue with several default routes on the bifrost
host when kolla_bifrost_dnsmasq_router needs to configure.

Change-Id: I2078da3ab3898c847b3c17054f429d74eb79aa37
Signed-off-by: Maksim Malchuk <maksim.malchuk@gmail.com>

ansible/kolla-bifrost.yml

@@ -26,7 +26,7 @@
       # Network configuration.
       kolla_bifrost_dhcp_pool_start: "{{ provision_oc_net_name | net_inspection_allocation_pool_start }}"
       kolla_bifrost_dhcp_pool_end: "{{ provision_oc_net_name | net_inspection_allocation_pool_end }}"
-      kolla_bifrost_dnsmasq_router: "{{ provision_oc_net_name | net_gateway }}"
+      kolla_bifrost_dnsmasq_router: "{{ provision_oc_net_name | net_inspection_gateway or provision_oc_net_name | net_gateway }}"
       kolla_bifrost_dnsmasq_dns_servers: "{{ resolv_nameservers | default([]) }}"
       kolla_bifrost_domain: "{{ resolv_domain | default }}"
       kolla_bifrost_download_ipa: "{{ not ipa_build_images | bool }}"

releasenotes/notes/bifrost-inspection-gateway-316ab384430ef8df.yaml

+---
+fixes:
+  - |
+    In production environments, the provision network may be separated from the
+    other networks, so in this case, if you want Bifrost's DHCP service provides
+    the correct gateway for the clients the ``inspection_gateway`` should be
+    used instead of the ``gateway`` attribute for the provision network. This
+    also avoids configuring the multiple IP gateways on a single host which
+    leads to unpredictable results.