apilint: Fix API lint issues

Fixes a bug where only the name instead of the fully qualified name was
considered when looking for a class, which lead to faulty results for inner
classes.

Test: python tools/apilint/apilint_test.py
Change-Id: Ib015669ed3faef21d2bdd16f1e27bc55c8669d70
(cherry picked from commit 2c5cacfd)