Remove mistaken System.Diagnostics inclusion from TfsWorkspace
Remove mistaken System.Diagnostics inclusion from TfsWorkspace

NathanLBCooper/git-tfs,kgybels/git-tfs,pmiossec/git-tfs,jeremy-sylvis-tmg/git-tfs,vzabavnov/git-tfs,git-tfs/git-tfs,kgybels/git-tfs,NathanLBCooper/git-tfs,PKRoma/git-tfs,NathanLBCooper/git-tfs,andyrooger/git-tfs,jeremy-sylvis-tmg/git-tfs,kgybels/git-tfs,jeremy-sylvis-tmg/git-tfs