Remove unused TreeEntrySafeHandle

Author: carlosmn

LibGit2Sharp/Core/Handles/TreeEntrySafeHandle.cs

@@ -282,7 +282,6 @@
     <Compile Include="Core\Handles\NotOwnedSafeHandleBase.cs" />
     <Compile Include="Core\Handles\TreeBuilderSafeHandle.cs" />
     <Compile Include="Core\Handles\SignatureSafeHandle.cs" />
-    <Compile Include="Core\Handles\TreeEntrySafeHandle.cs" />
     <Compile Include="DetachedHead.cs" />
     <Compile Include="Diff.cs" />
     <Compile Include="IRepository.cs" />