remove missed app.conf from project file

B3WeChat/B3WeChat.csproj

@@ -128,9 +128,6 @@
   <ItemGroup>
     <WCFMetadata Include="Service References\" />
   </ItemGroup>
-  <ItemGroup>
-    <None Include="app.config" />
-  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.