Workaround for FSharp build conditions

fsharp-msbuild.fsproj

<!-- fix some build bugs -->

<Choose>
    <When Condition="'$(VisualStudioVersion)' == '11.0'">
      <PropertyGroup Condition=" '$(FSharpTargetsPath)' == '' AND Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets') ">
        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
      </PropertyGroup>
    </When>
    <When Condition="'$(VisualStudioVersion)' == '15.0'">
      <PropertyGroup Condition=" '$(FSharpTargetsPath)' == '' AND Exists('$(MSBuildProgramFiles32)\Microsoft SDKs\F#\4.1\Framework\v4.0\Microsoft.FSharp.Targets') ">
        <FSharpTargetsPath>$(MSBuildProgramFiles32)\Microsoft SDKs\F#\4.1\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
      </PropertyGroup>
    </When>
    <Otherwise>
      <PropertyGroup Condition=" '$(FSharpTargetsPath)' == '' AND Exists('$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.FSharp.Targets') ">
        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.FSharp.Targets</FSharpTargetsPath>
      </PropertyGroup>
    </Otherwise>
  </Choose>
  <Import Project="$(FSharpTargetsPath)" />