Merge pull request #1087 from AGBrown/bugfix/ncrunch-item-group

Fixes #1053: exclude NCrunch ItemGroup when NCrunch not present

Author: JakeGinnivan

src/GitVersionTask/NugetAssets/GitVersionTask.targets

@@ -81,7 +81,7 @@
   </Target>
 
   <!--Support for ncrunch-->
-  <ItemGroup>
+  <ItemGroup Condition=" $(NCrunch) != '' ">
     <None Include="$(GitVersionTaskDir)GitVersionTask.dll">
       <Visible>False</Visible>
     </None>