Update pkgdb2's configuration of dogpile

Make it so that pkgdb2 relies on both memcached servers and that the difference
wsgi proccesses it happily live together.

Thanks to Ralph Bean for getting the configuration correct

roles/pkgdb2/templates/pkgdb2.cfg

@@ -29,7 +29,8 @@ ADMIN_GROUP = ['sysadmin-main', 'cvsadmin']
 PKGDB2_CACHE_BACKEND = 'dogpile.cache.memcached'
 PKGDB2_CACHE_KWARGS = {
     'arguments': {
-        'url': "127.0.0.1:11211",
+        'url': ["memcached01:11211", "memcached02:11211"],
+        'distributed_lock': True,
     }
 }