display: Request XI2.3

This matches commit:

http://git.gnome.org/browse/clutter/commit/?h=clutter-1.14&id=3e1450ba17fce90a8034cc525c67a87ff3cdd53d

Since XIQueryVersion, the bad API that it is, chooses the first client
version that it gets, we need to ensure that we pass XIQueryVersion the
new XI2.3 version, knowing fully well that Clutter won't be confused
by the new features.

https://bugzilla.gnome.org/show_bug.cgi?id=692877

src/core/display.c

@@ -778,7 +778,7 @@ meta_display_open (void)
   }
 
   {
-    int major = 2, minor = 2;
+    int major = 2, minor = 3;
     gboolean has_xi = FALSE;
 
     if (XQueryExtension (the_display->xdisplay,