Return commits in chronological order

Signed-off-by: Václav Valíček <valicek1994@gmail.com>

tests/lib/test_repo_tool.py

@@ -467,10 +467,14 @@ def test_list_commits(cloned_base_repo_obj):
 	assert cloned_base_repo_obj.list_commits(3)
 	count = 0
 	commits = set()
+	last_commit = ""
 	for commit in cloned_base_repo_obj.list_commits(20):
 		count += 1
 		commits.add(commit.hexsha)
+		last_commit = commit.hexsha
 	assert count == 20
+	# should be newest commit in repo
+	assert last_commit == "e0c7e2a72579e24657c05e875201011d2b48bf94"
 
 	assert commits == {
 		'93e97409040f6e4ba5cebc4ddca679a2d3203efa', 'd8cd3257e05dc4a3d0061b5320ef5efd0b45d840',