intel: remove a buffer equality test in _mesa_make_current()

Before, if we called glXMakeCurrent() to change a context's window binding
while an FBO was bound, we weren't updating the intel->driDrawable and
intel->driReadDrawable fields.  This could cause us to dereference a null
pointer elsewhere.

src/mesa/drivers/dri/intel/intel_context.c

@@ -993,41 +993,35 @@ intelMakeCurrent(__DRIcontextPrivate * driContextPriv,
 
       _mesa_make_current(&intel->ctx, &intel_fb->Base, readFb);
 
-      /* The drawbuffer won't always be updated by _mesa_make_current: 
-       */
-      if (intel->ctx.DrawBuffer == &intel_fb->Base) {
-
-	 if (intel->driReadDrawable != driReadPriv)
-	    intel->driReadDrawable = driReadPriv;
-
-	 if (intel->driDrawable != driDrawPriv) {
-	    if (driDrawPriv->swap_interval == (unsigned)-1) {
-	       int i;
-
-	       driDrawPriv->vblFlags = (intel->intelScreen->irq_active != 0)
-		  ? driGetDefaultVBlankFlags(&intel->optionCache)
-		 : VBLANK_FLAG_NO_IRQ;
-
-	       /* Prevent error printf if one crtc is disabled, this will
-		* be properly calculated in intelWindowMoved() next.
-		*/
-		driDrawPriv->vblFlags = intelFixupVblank(intel, driDrawPriv);
-
-	       (*psp->systemTime->getUST) (&intel_fb->swap_ust);
-	       driDrawableInitVBlank(driDrawPriv);
-	       intel_fb->vbl_waited = driDrawPriv->vblSeq;
-
-	       for (i = 0; i < 2; i++) {
-		  if (intel_fb->color_rb[i])
-		     intel_fb->color_rb[i]->vbl_pending = driDrawPriv->vblSeq;
-	       }
-	    }
-	    intel->driDrawable = driDrawPriv;
-	    intelWindowMoved(intel);
-	 }
+      intel->driReadDrawable = driReadPriv;
+
+      if (intel->driDrawable != driDrawPriv) {
+         if (driDrawPriv->swap_interval == (unsigned)-1) {
+            int i;
+
+            driDrawPriv->vblFlags = (intel->intelScreen->irq_active != 0)
+               ? driGetDefaultVBlankFlags(&intel->optionCache)
+               : VBLANK_FLAG_NO_IRQ;
 
-	 intel_draw_buffer(&intel->ctx, &intel_fb->Base);
+            /* Prevent error printf if one crtc is disabled, this will
+             * be properly calculated in intelWindowMoved() next.
+             */
+            driDrawPriv->vblFlags = intelFixupVblank(intel, driDrawPriv);
+
+            (*psp->systemTime->getUST) (&intel_fb->swap_ust);
+            driDrawableInitVBlank(driDrawPriv);
+            intel_fb->vbl_waited = driDrawPriv->vblSeq;
+
+            for (i = 0; i < 2; i++) {
+               if (intel_fb->color_rb[i])
+                  intel_fb->color_rb[i]->vbl_pending = driDrawPriv->vblSeq;
+            }
+         }
+         intel->driDrawable = driDrawPriv;
+         intelWindowMoved(intel);
       }
+
+      intel_draw_buffer(&intel->ctx, &intel_fb->Base);
    }
    else {
       _mesa_make_current(NULL, NULL, NULL);