Update memcache bind address to localhost

So that it can be accessed by the swift proxy
from this address.

Previously, it was binding to eth0 and swift proxy
was trying to access it via localhost.

examples/multi.pp

@@ -127,7 +127,7 @@ class role_swift_proxy inherits role_swift {
   package { 'curl': ensure => present }
 
   class { 'memcached':
-    listen_ip => $swift_local_net_ip,
+    listen_ip => '127.0.0.1',
   }
 
   # TODO should I enable swath in the default config?