util/disk_cache: finish all queue jobs in destroy instead of killing them

If there are queued shaders to be written to disk, wait for that.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/util/disk_cache.c

@@ -440,6 +440,7 @@ void
 disk_cache_destroy(struct disk_cache *cache)
 {
    if (cache && !cache->path_init_failed) {
+      util_queue_finish(&cache->cache_queue);
       util_queue_destroy(&cache->cache_queue);
       munmap(cache->index_mmap, cache->index_mmap_size);
    }