Restore BindingPath.pkgdef

This file was accidentally deleted in my earlier change, but without it
the Roslyn packages may refuse to load at startup.

src/VisualStudio/Setup/BindingPath.pkgdef

+[$RootKey$\BindingPaths\{5EABCC64-FDFC-478D-9123-DAE27341DE85}]
+"$PackageFolder$"=""

src/VisualStudio/Setup/VisualStudioSetup.csproj

@@ -191,6 +191,9 @@
       <DesignTime>True</DesignTime>
       <DependentUpon>VSPackage.resx</DependentUpon>
     </Compile>
+    <Content Include="BindingPath.pkgdef">
+      <IncludeInVSIX>true</IncludeInVSIX>
+    </Content>
     <Content Include="CSharpPackageRegistration.pkgdef">
       <IncludeInVSIX>true</IncludeInVSIX>
     </Content>
@@ -204,4 +207,4 @@
     <Import Project="..\..\..\build\VSL.Imports.Closed.targets" />
     <Import Project="$(SolutionDir)\.nuget\NuGet.targets" Condition="Exists('$(SolutionDir)\.nuget\NuGet.targets')" />
   </ImportGroup>
-</Project>
\ No newline at end of file
+</Project>