removed <PackageTargetFallback>

Author: jakubmisek

Directory.Build.targets

@@ -1,10 +1,5 @@
 <Project ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
-  <PropertyGroup>
-    <PackageTargetFallback Condition=" '$(TargetFramework)' == 'netstandard1.5' or '$(TargetFramework)' == 'netstandard1.6' ">$(PackageTargetFallback);dnxcore50</PackageTargetFallback>
-    <PackageTargetFallback Condition="'$(TargetFramework)'=='net45'">$(PackageTargetFallback);portable-net45+win8+wpa81+wp8</PackageTargetFallback>
-  </PropertyGroup>
-
   <!-- SourceLink -->
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0">