IGitTfsRemote: remove setter for property TfsRepositoryPath

The setter is not used and during the lifetime of the object the property
value shouldn't be changed. Remove it.

src/GitTfs/Core/DerivedGitTfsRemote.cs

@@ -74,7 +74,6 @@ namespace GitTfs.Core
         public string TfsRepositoryPath
         {
             get { return _tfsRepositoryPath; }
-            set { throw DerivedRemoteException; }
         }
 
         public string[] TfsSubtreePaths

src/GitTfs/Core/GitTfsRemote.cs

@@ -133,7 +133,7 @@ namespace GitTfs.Core
             set { Tfs.Password = value; }
         }
 
-        public string TfsRepositoryPath { get; set; }
+        public string TfsRepositoryPath { get; }
 
         /// <summary>
         /// Gets the TFS server-side paths of all subtrees of this remote.

src/GitTfs/Core/IGitTfsRemote.cs

@@ -32,7 +32,7 @@ namespace GitTfs.Core
         RemoteInfo RemoteInfo { get; }
         string Id { get; }
         string TfsUrl { get; set; }
-        string TfsRepositoryPath { get; set; }
+        string TfsRepositoryPath { get; }
         /// <summary>
         /// Gets the TFS server-side paths of all subtrees of this remote.
         /// Valid if the remote has subtrees, which occurs when <see cref="TfsRepositoryPath"/> is null.

src/GitTfsTest/Commands/InitBranchTest.cs

@@ -44,7 +44,7 @@ namespace GitTfs.Test.Commands
             var trunkGitTfsRemote = trunkGitTfsRemoteMock.Object;
             trunkGitTfsRemote.TfsUsername = "user";
             trunkGitTfsRemote.TfsPassword = "pwd";
-            trunkGitTfsRemote.TfsRepositoryPath = "$/MyProject/Trunk";
+            trunkGitTfsRemoteMock.SetupGet(x => x.TfsRepositoryPath).Returns("$/MyProject/Trunk");
             trunkGitTfsRemote.TfsUrl = "http://myTfsServer:8080/tfs";
 
             newBranchRemoteMock = Mock.Get(mocks.Get<IGitTfsRemote>()).SetupAllProperties();
@@ -115,7 +115,7 @@ namespace GitTfs.Test.Commands
             IGitTfsRemote existingBranchRemote = gitTfsRemoteMock.Object;
             existingBranchRemote.TfsUsername = "user";
             existingBranchRemote.TfsPassword = "pwd";
-            existingBranchRemote.TfsRepositoryPath = "$/MyProject/MyBranch";
+            gitTfsRemoteMock.SetupGet(x => x.TfsRepositoryPath).Returns("$/MyProject/MyBranch");
             existingBranchRemote.TfsUrl = "http://myTfsServer:8080/tfs";
 
             gitRepository.Name = nameof(gitRepository);
@@ -366,7 +366,7 @@ namespace GitTfs.Test.Commands
             var remote = remoteMock.Object;
             remote.TfsUsername = "user";
             remote.TfsPassword = "pwd";
-            remote.TfsRepositoryPath = "$/MyProject/Trunk";
+            remoteMock.SetupGet(x => x.TfsRepositoryPath).Returns("$/MyProject/Trunk");
             remote.TfsUrl = "http://myTfsServer:8080/tfs";
             remoteMock.SetupGet(x => x.Tfs).Returns(new TfsHelper(mocks.Container, null));