Fix malformed patch format.

For some reason, the leading spaces were missing.

util/openflow-patches/datapath.patch

@@ -12,7 +12,7 @@ index 4a4d3a2..365aa25 100644
  
  /* Strings to describe the manufacturer, hardware, and software.  This data
   * is queriable through the switch description stats message. */
-@@ -259,7 +262,11 @@ send_openflow_skb(const struct datapath *dp,
+@@ -259,6 +262,10 @@ send_openflow_skb(const struct datapath *dp,
                   struct sk_buff *skb, const struct sender *sender)
  {
         return (sender