dbghelp: Removed call to registered callback when unloading a module.

First, native dbghelp doesn't do it, and it crashed windbg, likely
because we got the undocumented arguments wrong.
diff --git a/dlls/dbghelp/module.c b/dlls/dbghelp/module.c
index 26b847a..9b138e3 100644
--- a/dlls/dbghelp/module.c
+++ b/dlls/dbghelp/module.c
@@ -520,9 +520,9 @@
     HeapFree(GetProcessHeap(), 0, (char*)module->sources);
     HeapFree(GetProcessHeap(), 0, module->addr_sorttab);
     pool_destroy(&module->pool);
-    if (module->module.SymType != SymNone)
-        pcs_callback(pcs, CBA_SYMBOLS_UNLOADED, NULL);
-
+    /* native dbghelp doesn't invoke registered callback(,CBA_SYMBOLS_UNLOADED,) here
+     * so do we
+     */
     for (p = &pcs->lmodules; *p; p = &(*p)->next)
     {
         if (*p == module)