Remove repo open immediately after init in test

Calling git_repository_open immediately after git_repository_init
results in memory leaks.

tests-clay/object/commit/commitstagedfile.c

@@ -7,7 +7,6 @@ void test_object_commit_commitstagedfile__initialize(void)
 {
 	cl_fixture("treebuilder");
 	cl_git_pass(git_repository_init(&repo, "treebuilder/", 0));
-	cl_git_pass(git_repository_open(&repo, "treebuilder/.git"));
 	cl_assert(repo != NULL);
 }