Fix build warnings by not relying on obsolete properties

Author: nulltoken

LibGit2Sharp.Tests/FilterFixture.cs

@@ -304,7 +304,7 @@ private FileInfo CheckoutFileForSmudge(string repoPath, string branchName, strin
         private static FileInfo CommitFileOnBranch(Repository repo, string branchName, String content)
         {
             var branch = repo.CreateBranch(branchName);
-            repo.Checkout(branch.Name);
+            repo.Checkout(branch.FriendlyName);
 
             FileInfo expectedPath = StageNewFile(repo, content);
             repo.Commit("Commit");

LibGit2Sharp.Tests/FilterSubstitutionCipherFixture.cs

@@ -35,7 +35,7 @@ public void SmugdeIsNotCalledForFileWhichDoesNotMatchAnAttributeEntry()
                 Assert.Equal(0, filter.SmudgeCalledCount);
 
                 var branch = repo.CreateBranch("delete-files");
-                repo.Checkout(branch.Name);
+                repo.Checkout(branch.FriendlyName);
 
                 DeleteFile(repo, fileName);
 
@@ -75,7 +75,7 @@ public void CorrectlyEncodesAndDecodesInput()
                 Assert.Equal(0, filter.SmudgeCalledCount);
 
                 var branch = repo.CreateBranch("delete-files");
-                repo.Checkout(branch.Name);
+                repo.Checkout(branch.FriendlyName);
 
                 DeleteFile(repo, fileName);
 
@@ -181,7 +181,7 @@ public void SmudgeIsCalledIfAttributeEntryMatches(string filterAttribute, string
                 CommitOnBranchAndReturnDatabaseBlob(repo, fileName, decodedInput);
 
                 var branch = repo.CreateBranch("delete-files");
-                repo.Checkout(branch.Name);
+                repo.Checkout(branch.FriendlyName);
 
                 DeleteFile(repo, fileName);