Edited Issue: Installing v2 of the Microsoft.AspNet.Webpages NuGet package fails to remove the webPages:Version appSetting if it exists [438]

1. Create a Razor v1 web site
2. Open web.config and add the following entry in <appSettings />.

<add key="webPages:Version" value="1.0.0.0" />

3. Open the NuGet package manager and install version 2 of the package Microsoft.AspNet.Webpages.

Result: In web.config, the app setting isn't updated to 2.0, even as the assembly references are. If you attempt to build the site, compilation will fail with multiple errors of the form

The type 'System.Web.WebPages.HelperPage' exists in both 'c:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.Web.WebPages\v4.0_2.0.0.0__31bf3856ad364e35\System.Web.WebPages.dll' and 'c:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.Web.WebPages\v4.0_1.0.0.0__31bf3856ad364e35\System.Web.WebPages.dll' c:\Users\fwtlaba\AppData\Local\Temp\Temporary ASP.NET Files\school\37312387\916963f9\App_Code.np9dbukn.8.cs

Expected: We should transform web.config to update the webpages:Version setting as well.