Fix memory leak

Author: JasonGoemaat

LibGit2Sharp/Core/NativeMethods.cs

@@ -1606,14 +1606,10 @@ internal static extern void git_strarray_free(
         /// the submodule repo and perform the clone step as needed.  Lastly, call
         /// 'git_submodule_add_finalize()' to wrap up adding the new submodule and
         /// .gitmodules to the index to be ready to commit.
+        ///
+        /// In our case, go ahead and do the clone first.  The setup can be done
+        /// with the directory contents already in place.
         /// </summary>
-        //[DllImport(libgit2)]
-        //internal static extern unsafe int git_submodule_add_setup(
-        //    out git_submodule* reference,
-        //    git_repository* repo,
-        //    [CustomMarshaler(typeof(StrictUtf8Marshaler), typeof(string))] byte* url,
-        //    [CustomMarshaler(typeof(StrictUtf8Marshaler), typeof(string))] byte* path,
-        //    int use_gitlink);
         [DllImport(libgit2)]
         private static extern unsafe int git_submodule_add_setup(
             out git_submodule* reference,

LibGit2Sharp/SubmoduleCollection.cs

@@ -60,6 +60,7 @@ public virtual void Add(string url, string path, int useGitLink)
         {
             SubmoduleHandle handle = Proxy.git_submodule_add_setup(repo.Handle, url, path, useGitLink);
             Proxy.git_submodule_add_finalize(handle);
+            handle.Free();
         }
 
         /// <summary>