raise DefaultTimeout from 100ms to 500ms

Various memcached concentrator things (and things with disks) are more
common now (and TLS implementations with more round-trips). The
assumption of all memcached access being within the same rack/LAN
might no longer be appropriate.

Updates #114

Signed-off-by: Brad Fitzpatrick <brad@danga.com>

Author: bradfitz

memcache/memcache.go

@@ -65,7 +65,7 @@ var (
 
 const (
 	// DefaultTimeout is the default socket read/write timeout.
-	DefaultTimeout = 100 * time.Millisecond
+	DefaultTimeout = 500 * time.Millisecond
 
 	// DefaultMaxIdleConns is the default maximum number of idle connections
 	// kept for any single address.