tests-clar/notes: init oid before using

Reported-by: Carlos Martín Nieto <carlos@cmartin.tk>
Signed-off-by: schu <schu-github@schulog.org>

tests-clar/notes/notes.c

@@ -26,6 +26,7 @@ void test_notes_notes__1(void)
 	git_oid oid, note_oid;
 
 	cl_git_pass(git_signature_now(&_sig, "alice", "alice@example.com"));
+	cl_git_pass(git_oid_fromstr(&oid, "8496071c1b46c854b31185ea97743be6a8774479"));
 
 	cl_git_pass(git_note_create(&note_oid, _repo, _sig, _sig, "refs/notes/some/namespace", &oid, "hello world\n"));
 	cl_git_pass(git_note_create(&note_oid, _repo, _sig, _sig, NULL, &oid, "hello world\n"));