FakeItEasy: Rake build error when having both 14 and 15 msbuild

This is what I’m getting when running bundle exec rake

D, [2016-05-22T23:07:20.990390 #5656] DEBUG -- : Executing Exec: "F:/Projects/github/_mvas/FakeItEasy/.nuget/NuGet.exe" restore FakeItEasy.sln
MSBuild auto-detection: using msbuild version '15.0' from 'C:\Program Files (x86)\MSBuild\15.0\bin'.
Error parsing solution file at F:\Projects\github\_mvas\FakeItEasy\FakeItEasy.sln: This version of msbuild is not supported: 'Microsoft.Build, Version=15.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
F, [2016-05-22T23:07:21.503093 #5656] FATAL -- : Exec Failed. See Build Log For Detail

I have MSBuild 15 and 14 both installed, seems like nuget should be told to use 14 strictly