ole32: Fix QueryInterface for IErrorInfo to return IUnknown pointer.

dlls/ole32/errorinfo.c

@@ -160,7 +160,7 @@ static HRESULT WINAPI IErrorInfoImpl_QueryInterface(
 
 	*ppvoid = NULL;
 
-	if(IsEqualIID(riid, &IID_IErrorInfo))
+	if (IsEqualIID(riid, &IID_IUnknown) || IsEqualIID(riid, &IID_IErrorInfo))
 	{
 	  *ppvoid = &This->IErrorInfo_iface;
 	}

dlls/ole32/tests/errorinfo.c

@@ -47,10 +47,15 @@ static void test_error_info(void)
     static WCHAR wszDescription[] = {'F','a','i','l','e','d',' ','S','p','r','o','c','k','e','t',0};
     static WCHAR wszHelpFile[] = {'s','p','r','o','c','k','e','t','.','h','l','p',0};
     static WCHAR wszSource[] = {'s','p','r','o','c','k','e','t',0};
+    IUnknown *unk;
 
     hr = CreateErrorInfo(&pCreateErrorInfo);
     ok_ole_success(hr, "CreateErrorInfo");
 
+    hr = ICreateErrorInfo_QueryInterface(pCreateErrorInfo, &IID_IUnknown, (void**)&unk);
+    ok_ole_success(hr, "QI");
+    IUnknown_Release(unk);
+
     hr = ICreateErrorInfo_SetDescription(pCreateErrorInfo, NULL);
     ok_ole_success(hr, "ICreateErrorInfo_SetDescription");
 
@@ -78,6 +83,10 @@ static void test_error_info(void)
     hr = ICreateErrorInfo_QueryInterface(pCreateErrorInfo, &IID_IErrorInfo, (void **)&pErrorInfo);
     ok_ole_success(hr, "ICreateErrorInfo_QueryInterface");
 
+    hr = IErrorInfo_QueryInterface(pErrorInfo, &IID_IUnknown, (void**)&unk);
+    ok_ole_success(hr, "QI");
+    IUnknown_Release(unk);
+
     ICreateErrorInfo_Release(pCreateErrorInfo);
 
     hr = SetErrorInfo(0, pErrorInfo);