[cache] Clear stash if called with called with NULL

src/cache.c

@@ -1218,7 +1218,7 @@ cache_artwork_stash_impl(void *arg, int *retval)
 
   cmdarg = arg;
 
-  /* Clear current stash */
+  // Clear current stash
   if (g_stash.path)
     {
       free(g_stash.path);
@@ -1226,6 +1226,13 @@ cache_artwork_stash_impl(void *arg, int *retval)
       memset(&g_stash, 0, sizeof(struct stash));
     }
 
+  // If called with no evbuf then we are done, we just needed to clear the stash
+  if (!cmdarg->evbuf)
+    {
+      *retval = 0;
+      return COMMAND_END;
+    }
+
   g_stash.size = evbuffer_get_length(cmdarg->evbuf);
   g_stash.data = malloc(g_stash.size);
   if (!g_stash.data)