i915: Don't segfault on buffer allocation error

src/gallium/winsys/egl_drm/intel/intel_egl.c

@@ -479,12 +479,13 @@ drm_show_screen_surface_mesa(_EGLDriver *drv, EGLDisplay dpy,
 		DRM_BO_FLAG_NO_EVICT,
 		DRM_BO_HINT_DONT_FENCE, &scrn->buffer);
 
-	prettyColors(drm_drv->device->drmFD, scrn->buffer.handle, pitch);
 	if (ret) {
 		printf("failed to create framebuffer (ret %d)\n", ret);
 		return EGL_FALSE;
 	}
 
+	prettyColors(drm_drv->device->drmFD, scrn->buffer.handle, pitch);
+
 	ret = drmModeAddFB(drm_drv->device->drmFD, mode->Width, mode->Height,
 			32, 32, pitch,
 			scrn->buffer.handle,