Correctly release resources in xdisplaycheck.

tools/xdisplaycheck/xdisplaycheck.cc

Index: tools/xdisplaycheck/xdisplaycheck.cc
===================================================================
--- tools/xdisplaycheck/xdisplaycheck.cc	(revision 210169)
+++ tools/xdisplaycheck/xdisplaycheck.cc	(working copy)
@@ -41,6 +41,7 @@
     if (display) {
       fprintf(stderr, "Found unexpected connectable display %s\n",
               XDisplayName(NULL));
+      XCloseDisplay(display);
     }
     // Return success when we got an unexpected display so that the code
     // without the --noserver is the same, but slow, rather than inverted.
@@ -88,6 +89,7 @@
   fprintf(stderr,
       "XInput2 verified initially sane on %s.\n", XDisplayName(NULL));
 #endif
-
+  if (display)
+    XCloseDisplay(display);
   return 0;
 }