When a commit is referenced by a branch or tag the commit subject-
line will be suffixed with the proper decorations, hence the test
for this line needs to be updated.
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Both cgit_print_diff() and cgit_diff_tree() handles root commits nicely,
but cgit_print_commit() forgot to check the case of 0 parents.
This fixes it, and adds tests to avoid future regressions.
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
