More test stabilization against git2 temp file

Author: AArnott

src/NerdBank.GitVersioning.Tests/ReleaseManagerTests.cs

@@ -377,7 +377,6 @@ public void PrepareRelease_MasterWithVersionDecrement(string initialVersion, str
     public void PrepareRelease_DetachedHead()
     {
         this.InitializeSourceControl();
-        this.Ignore_git2_UntrackedFile();
         this.WriteVersionFile("1.0", "-alpha");
         Commands.Checkout(this.Repo, this.Repo.Head.Commits.First());
         var ex = Assert.Throws<ReleasePreparationException>(() => new ReleaseManager().PrepareRelease(this.RepoPath));
@@ -553,6 +552,12 @@ public void PrepareRelease_JsonOutputWhenUpdatingReleaseBranch()
         }
     }
 
+    protected override void InitializeSourceControl()
+    {
+        base.InitializeSourceControl();
+        this.Ignore_git2_UntrackedFile();
+    }
+
     private void AssertError(Action testCode, ReleasePreparationError expectedError)
     {
         var ex = Assert.Throws<ReleasePreparationException>(testCode);

src/NerdBank.GitVersioning.Tests/RepoTestBase.cs

@@ -68,7 +68,7 @@ protected virtual void Dispose(bool disposing)
         }
     }
 
-    protected void InitializeSourceControl()
+    protected virtual void InitializeSourceControl()
     {
         Repository.Init(this.RepoPath);
         this.Repo = new Repository(this.RepoPath);