Remove stale patch file--this is included in the distfile.

modular-xorg-server/patches/patch-ab

@@ -1,28 +0,0 @@
-$NetBSD: patch-ab,v 1.7 2008/03/03 03:11:11 bsadewitz Exp $
-
-Differentiate between direct and indirect contexts.
-
---- GL/glx/glxdri.c.orig	2008-02-18 00:16:52.000000000 -0500
-+++ GL/glx/glxdri.c
-@@ -598,6 +598,9 @@ __glXDRIscreenCreateContext(__GLXscreen 
-     else
- 	sharePrivate = NULL;
- 
-+    if (baseShareContext && baseShareContext->isDirect)
-+        return NULL;
-+
-     context = xalloc(sizeof *context);
-     if (context == NULL)
- 	return NULL;
-@@ -617,6 +620,11 @@ __glXDRIscreenCreateContext(__GLXscreen 
- 					   0, /* render type */
- 					   sharePrivate,
- 					   &context->driContext);
-+    
-+    if (!context->driContext.private) {
-+    	xfree(context);
-+    	return NULL;
-+    }
- 
-     context->driContext.mode = modes;
-