Prevent NPE when converting api to xml.

If a stub ClassInfo is generated, calling 'showAnnotations' on it
would throw a NPE.

Bug: 14063625
Change-Id: Ic3af51ab7e488c599b87449b30b46e2ecfe03112
(cherry picked from commit baf6bc51adf56a5ed569f9ab1edb31980324fee6)
1 file changed