nginx: fix the creation of the webroot directory.

nginx/tasks/nginx-virtualhosts.yml

@@ -1,7 +1,7 @@
 ---
 - block:
     - name: Create the nginx webroot if different from the default
-      file: dest={{ nginx_webroot }} mode=0755
+      file: dest={{ nginx_webroot }} state=directory mode=0755
       when: nginx_webroot != '/usr/share/nginx/html'
 
     - name: Install the nginx virtualhost files