Fix nginx to work with RedHat/CentOS

The CentOS version of nginx uses a conf.d style directory for virtual
hosts instead of a sites-available/sites-enabled approach.

We can add a var to select where the configuration file is placed, and
only perform the link on Debian based systems.

Change-Id: I00b8af093e17a4450b642a1534b8ec647c9d2513

tasks/keystone_nginx.yml

@@ -37,7 +37,7 @@
 - name: Configure virtual hosts
   template:
     src: keystone_nginx.conf.j2
-    dest: "/etc/nginx/sites-available/{{ item }}.conf"
+    dest: "/etc/nginx/{{ keystone_nginx_conf_path }}/{{ item }}.conf"
   with_items: keystone_wsgi_program_names
   notify: Restart Nginx
 
@@ -47,4 +47,5 @@
     path: "/etc/nginx/sites-enabled/{{ item }}.conf"
     state: link
   with_items: keystone_wsgi_program_names
+  when: ansible_os_family == "Debian"
   notify: Restart Nginx

vars/redhat-7.yml

@@ -72,4 +72,6 @@ keystone_apache_configs:
   - { src: "keystone-httpd.conf.j2", dest: "/etc/httpd/conf.d/keystone-httpd.conf" }
   - { src: "keystone-httpd-mpm.conf.j2", dest: "/etc/httpd/conf.modules.d/mpm_{{ keystone_httpd_mpm_backend }}.conf" }
 
+keystone_nginx_conf_path: "conf.d"
+
 keystone_system_service_name: httpd

vars/ubuntu-14.04.yml

@@ -65,4 +65,6 @@ keystone_apache_configs:
   - { src: "keystone-httpd.conf.j2", dest: "/etc/apache2/sites-available/keystone-httpd.conf" }
   - { src: "keystone-httpd-mpm.conf.j2", dest: "/etc/apache2/mods-available/mpm_{{ keystone_httpd_mpm_backend }}.conf" }
 
+keystone_nginx_conf_path: "sites-available"
+
 keystone_system_service_name: apache2

vars/ubuntu-16.04.yml

@@ -65,4 +65,6 @@ keystone_apache_configs:
   - { src: "keystone-httpd.conf.j2", dest: "/etc/apache2/sites-available/keystone-httpd.conf" }
   - { src: "keystone-httpd-mpm.conf.j2", dest: "/etc/apache2/mods-available/mpm_{{ keystone_httpd_mpm_backend }}.conf" }
 
+keystone_nginx_conf_path: "sites-available"
+
 keystone_system_service_name: apache2