Repository: allow Options with a bare repo

Fix a minor logic bug, where we assumed that any RepositoryOptions
would provide a workdir and index such that the repo is not bare.

Author: Edward Thomson

LibGit2Sharp.Tests/RepositoryOptionsFixture.cs

@@ -52,6 +52,18 @@ public void CanOpenABareRepoAsIfItWasAStandardOneWithANonExisitingIndexFile()
             }
         }
 
+        [Fact]
+        public void CanOpenABareRepoWithOptions()
+        {
+            var options = new RepositoryOptions { GlobalConfigurationLocation = null };
+
+            string path = SandboxBareTestRepo();
+            using (var repo = new Repository(path, options))
+            {
+                Assert.True(repo.Info.IsBare);
+            }
+        }
+
         [Fact]
         public void CanProvideADifferentWorkDirToAStandardRepo()
         {

LibGit2Sharp/Repository.cs

@@ -76,7 +76,10 @@ public Repository(string path, RepositoryOptions options = null)
                             "When overriding the opening of a bare repository, both RepositoryOptions.WorkingDirectoryPath an RepositoryOptions.IndexPath have to be provided.");
                     }
 
-                    isBare = false;
+                    if (!isWorkDirNull)
+                    {
+                        isBare = false;
+                    }
 
                     if (!isIndexNull)
                     {