Multi-fw targeting w/ spaces aren't being trimmed for paket.restore.cached file gen

[haf]

➜  expecto git:(feature/netstandard1.6) dotnet build
/Users/h/dev/haf/expecto/.paket/Paket.Restore.targets(86,5): warning : Detected a change ('target-framework 'netstandard1.6'') in the project file '/Users/h/dev/haf/expecto/Expecto/Expecto.fsproj', calling paket restore [/Users/h/dev/haf/expecto/Expecto/Expecto.fsproj]
/Users/h/dev/haf/expecto/.paket/Paket.Restore.targets(90,5): error : A paket file for the framework 'netstandard1.6' is missing. Please delete 'paket-files/paket.restore.cached' and call 'paket restore'. [/Users/h/dev/haf/expecto/Expecto/Expecto.fsproj]
^CAttempting to cancel the build...

➜  expecto git:(feature/netstandard1.6) rm paket-files/paket.restore.cached
➜  expecto git:(feature/netstandard1.6) mono .paket/paket.exe restore
Paket version 5.93.0
 - /Users/h/dev/haf/expecto/Expecto/obj/Expecto.fsproj.net461.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto/obj/Expecto.fsproj. netstandard1.6.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.BenchmarkDotNet/obj/Expecto.BenchmarkDotNet.fsproj.net461.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.BenchmarkDotNet/obj/Expecto.BenchmarkDotNet.fsproj. netcoreapp1.1.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.FsCheck/obj/Expecto.FsCheck.fsproj.net461.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.FsCheck/obj/Expecto.FsCheck.fsproj. netstandard1.6.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.Sample/obj/Expecto.Sample.fsproj.net461.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.Sample/obj/Expecto.Sample.fsproj. netcoreapp1.1.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.Tests/obj/Expecto.Tests.fsproj.net461.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.Tests/obj/Expecto.Tests.fsproj. netcoreapp1.1.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.Tests.CSharp/obj/Expecto.Tests.CSharp.csproj.net461.paket.resolved created
 - /Users/h/dev/haf/expecto/Expecto.Tests.CSharp/obj/Expecto.Tests.CSharp.csproj. netcoreapp1.1.paket.resolved created
 - /Users/h/dev/haf/expecto/testdata/Expecto.Focused.Tests/obj/Expecto.Focused.Tests.fsproj.net461.paket.resolved created
 - /Users/h/dev/haf/expecto/testdata/Expecto.Focused.Tests/obj/Expecto.Focused.Tests.fsproj. netcoreapp1.1.paket.resolved created
Performance:
 - Disk IO: 645 milliseconds
 - Runtime: 3 seconds
➜  expecto git:(feature/netstandard1.6) dotnet build
/Users/h/dev/haf/expecto/.paket/Paket.Restore.targets(86,5): warning : Detected a change ('target-framework 'netstandard1.6'') in the project file '/Users/h/dev/haf/expecto/Expecto/Expecto.fsproj', calling paket restore [/Users/h/dev/haf/expecto/Expecto/Expecto.fsproj]
/Users/h/dev/haf/expecto/.paket/Paket.Restore.targets(90,5): error : A paket file for the framework 'netstandard1.6' is missing. Please delete 'paket-files/paket.restore.cached' and call 'paket restore'. [/Users/h/dev/haf/expecto/Expecto/Expecto.fsproj]
^CAttempting to cancel the build...

From haf/expecto#197

[haf]

This is a bug in paket, stemming from not trimming the values of the list of target frameworks:

     <TargetFrameworks>net461; netcoreapp1.1</TargetFrameworks>

   - /Users/h/dev/haf/expecto/testdata/Expecto.Focused.Tests/obj/Expecto.Focused.Tests.fsproj.net461.paket.resolved created
   - /Users/h/dev/haf/expecto/testdata/Expecto.Focused.Tests/obj/Expecto.Focused.Tests.fsproj. netcoreapp1.1.paket.resolved created