atl100: Fixed NULL catmap handling in AtlRegisterClassCategoriesHelper.

dlls/atl100/atl.c

@@ -429,6 +429,9 @@ HRESULT WINAPI AtlRegisterClassCategoriesHelper(REFCLSID clsid, const struct _AT
 
     TRACE("(%s %p %x)\n", debugstr_guid(clsid), catmap, reg);
 
+    if(!catmap)
+        return S_OK;
+
     if(!catreg) {
         ICatRegister *new_catreg;
 

dlls/atl100/tests/atl.c

@@ -154,6 +154,13 @@ static void test_regcat(void)
     test_key_not_exists(HKEY_CLASSES_ROOT, "CLSID\\{" CLSID_TEST_STR "}\\Implemented Categories");
     test_key_not_exists(HKEY_CLASSES_ROOT, "CLSID\\{" CLSID_TEST_STR "}\\Required Categories");
     test_key_exists(HKEY_CLASSES_ROOT, "CLSID\\{" CLSID_TEST_STR "}");
+
+    ok(RegDeleteKeyA(HKEY_CLASSES_ROOT, "CLSID\\{" CLSID_TEST_STR "}") == ERROR_SUCCESS, "Could not delete key\n");
+
+    hres = AtlRegisterClassCategoriesHelper(&CLSID_Test, NULL, TRUE);
+    ok(hres == S_OK, "AtlRegisterClassCategoriesHelper failed: %08x\n", hres);
+
+    test_key_not_exists(HKEY_CLASSES_ROOT, "CLSID\\{" CLSID_TEST_STR "}");
 }
 
 static void test_typelib(void)